Index: lib/Target/WebAssembly/WebAssemblyISelLowering.h
===================================================================
--- lib/Target/WebAssembly/WebAssemblyISelLowering.h
+++ lib/Target/WebAssembly/WebAssemblyISelLowering.h
@@ -54,6 +54,8 @@
                                StringRef Constraint, MVT VT) const override;
   bool isCheapToSpeculateCttz() const override;
   bool isCheapToSpeculateCtlz() const override;
+  bool isLegalAddressingMode(const DataLayout &DL, const AddrMode &AM, Type *Ty,
+                             unsigned AS) const override;
 
   SDValue LowerCall(CallLoweringInfo &CLI,
                     SmallVectorImpl<SDValue> &InVals) const override;
Index: lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
===================================================================
--- lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
+++ lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
@@ -261,6 +261,24 @@
   return true;
 }
 
+bool WebAssemblyTargetLowering::isLegalAddressingMode(const DataLayout &DL,
+                                                      const AddrMode &AM,
+                                                      Type *Ty,
+                                                      unsigned AS) const {
+  // WebAssembly offsets are added as unsigned without wrapping. The
+  // isLegalAddressingMode gives us no way to determine if wrapping could be
+  // happening, so we approximate this by accepting only non-negative offsets.
+  if (AM.BaseOffs < 0)
+    return false;
+
+  // WebAssembly has no scale register operands.
+  if (AM.Scale != 0)
+    return false;
+
+  // Everything else is legal.
+  return true;
+}
+
 //===----------------------------------------------------------------------===//
 // WebAssembly Lowering private implementation.
 //===----------------------------------------------------------------------===//
@@ -408,7 +426,8 @@
     if (In.Flags.isInConsecutiveRegs())
       fail(DL, DAG, "WebAssembly hasn't implemented cons regs return values");
     if (In.Flags.isInConsecutiveRegsLast())
-      fail(DL, DAG, "WebAssembly hasn't implemented cons regs last return values");
+      fail(DL, DAG,
+           "WebAssembly hasn't implemented cons regs last return values");
     // Ignore In.getOrigAlign() because all our arguments are passed in
     // registers.
     Tys.push_back(In.VT);
@@ -551,9 +570,9 @@
   assert(GA->getTargetFlags() == 0 && "WebAssembly doesn't set target flags");
   if (GA->getAddressSpace() != 0)
     fail(DL, DAG, "WebAssembly only expects the 0 address space");
-  return DAG.getNode(WebAssemblyISD::Wrapper, DL, VT,
-                     DAG.getTargetGlobalAddress(GA->getGlobal(), DL, VT,
-                                                GA->getOffset()));
+  return DAG.getNode(
+      WebAssemblyISD::Wrapper, DL, VT,
+      DAG.getTargetGlobalAddress(GA->getGlobal(), DL, VT, GA->getOffset()));
 }
 
 SDValue
Index: lib/Target/WebAssembly/WebAssemblyInstrMemory.td
===================================================================
--- lib/Target/WebAssembly/WebAssemblyInstrMemory.td
+++ lib/Target/WebAssembly/WebAssemblyInstrMemory.td
@@ -14,14 +14,20 @@
 
 // TODO:
 //  - HasAddr64
-//  - WebAssemblyTargetLowering::isLegalAddressingMode
 //  - WebAssemblyTargetLowering having to do with atomics
-//  - Each has optional alignment and immediate byte offset.
+//  - Each has optional alignment.
 
 // WebAssembly has i8/i16/i32/i64/f32/f64 memory types, but doesn't have i8/i16
 // local types. These memory-only types instead zero- or sign-extend into local
 // types when loading, and truncate when storing.
 
+// WebAssembly constant offsets are performed as unsigned with infinite
+// precision, so we need to check for NoUnsignedWrap so that we don't fold an
+// offset for an add that needs wrapping.
+def regPlusImm : PatFrag<(ops node:$off, node:$addr),
+                         (add node:$addr, node:$off),
+                         [{ return N->getFlags()->hasNoUnsignedWrap(); }]>;
+
 let Defs = [ARGUMENTS] in {
 
 // Basic load.
@@ -34,6 +40,64 @@
 def LOAD_F64 : I<(outs F64:$dst), (ins i32imm:$off, I32:$addr), [],
                  "f64.load\t$dst, $off($addr)">;
 
+} // Defs = [ARGUMENTS]
+
+// Select loads with no constant offset.
+def : Pat<(i32 (load I32:$addr)), (LOAD_I32 0, $addr)>;
+def : Pat<(i64 (load I32:$addr)), (LOAD_I64 0, $addr)>;
+def : Pat<(f32 (load I32:$addr)), (LOAD_F32 0, $addr)>;
+def : Pat<(f64 (load I32:$addr)), (LOAD_F64 0, $addr)>;
+
+// Select loads with a constant offset.
+def : Pat<(i32 (load (regPlusImm imm:$off, I32:$addr))),
+          (LOAD_I32 imm:$off, $addr)>;
+def : Pat<(i64 (load (regPlusImm imm:$off, I32:$addr))),
+          (LOAD_I64 imm:$off, $addr)>;
+def : Pat<(f32 (load (regPlusImm imm:$off, I32:$addr))),
+          (LOAD_F32 imm:$off, $addr)>;
+def : Pat<(f64 (load (regPlusImm imm:$off, I32:$addr))),
+          (LOAD_F64 imm:$off, $addr)>;
+def : Pat<(i32 (load (regPlusImm tglobaladdr:$off, I32:$addr))),
+          (LOAD_I32 tglobaladdr:$off, $addr)>;
+def : Pat<(i64 (load (regPlusImm tglobaladdr:$off, I32:$addr))),
+          (LOAD_I64 tglobaladdr:$off, $addr)>;
+def : Pat<(f32 (load (regPlusImm tglobaladdr:$off, I32:$addr))),
+          (LOAD_F32 tglobaladdr:$off, $addr)>;
+def : Pat<(f64 (load (regPlusImm tglobaladdr:$off, I32:$addr))),
+          (LOAD_F64 tglobaladdr:$off, $addr)>;
+def : Pat<(i32 (load (regPlusImm texternalsym:$off, I32:$addr))),
+          (LOAD_I32 texternalsym:$off, $addr)>;
+def : Pat<(i64 (load (regPlusImm texternalsym:$off, I32:$addr))),
+          (LOAD_I64 texternalsym:$off, $addr)>;
+def : Pat<(f32 (load (regPlusImm texternalsym:$off, I32:$addr))),
+          (LOAD_F32 texternalsym:$off, $addr)>;
+def : Pat<(f64 (load (regPlusImm texternalsym:$off, I32:$addr))),
+          (LOAD_F64 texternalsym:$off, $addr)>;
+
+// Select loads with just a constant offset.
+def : Pat<(i32 (load imm:$off)), (LOAD_I32 imm:$off, (CONST_I32 0))>;
+def : Pat<(i64 (load imm:$off)), (LOAD_I64 imm:$off, (CONST_I32 0))>;
+def : Pat<(f32 (load imm:$off)), (LOAD_F32 imm:$off, (CONST_I32 0))>;
+def : Pat<(f64 (load imm:$off)), (LOAD_F64 imm:$off, (CONST_I32 0))>;
+def : Pat<(i32 (load (WebAssemblywrapper tglobaladdr:$off))),
+          (LOAD_I32 tglobaladdr:$off, (CONST_I32 0))>;
+def : Pat<(i64 (load (WebAssemblywrapper tglobaladdr:$off))),
+          (LOAD_I64 tglobaladdr:$off, (CONST_I32 0))>;
+def : Pat<(f32 (load (WebAssemblywrapper tglobaladdr:$off))),
+          (LOAD_F32 tglobaladdr:$off, (CONST_I32 0))>;
+def : Pat<(f64 (load (WebAssemblywrapper tglobaladdr:$off))),
+          (LOAD_F64 tglobaladdr:$off, (CONST_I32 0))>;
+def : Pat<(i32 (load (WebAssemblywrapper texternalsym:$off))),
+          (LOAD_I32 texternalsym:$off, (CONST_I32 0))>;
+def : Pat<(i64 (load (WebAssemblywrapper texternalsym:$off))),
+          (LOAD_I64 texternalsym:$off, (CONST_I32 0))>;
+def : Pat<(f32 (load (WebAssemblywrapper texternalsym:$off))),
+          (LOAD_F32 texternalsym:$off, (CONST_I32 0))>;
+def : Pat<(f64 (load (WebAssemblywrapper texternalsym:$off))),
+          (LOAD_F64 texternalsym:$off, (CONST_I32 0))>;
+
+let Defs = [ARGUMENTS] in {
+
 // Extending load.
 def LOAD8_S_I32  : I<(outs I32:$dst), (ins i32imm:$off, I32:$addr), [],
                      "i32.load8_s\t$dst, $off($addr)">;
@@ -58,12 +122,6 @@
 
 } // Defs = [ARGUMENTS]
 
-// Select loads with no constant offset.
-def : Pat<(i32 (load I32:$addr)), (LOAD_I32 0, $addr)>;
-def : Pat<(i64 (load I32:$addr)), (LOAD_I64 0, $addr)>;
-def : Pat<(f32 (load I32:$addr)), (LOAD_F32 0, $addr)>;
-def : Pat<(f64 (load I32:$addr)), (LOAD_F64 0, $addr)>;
-
 // Select extending loads with no constant offset.
 def : Pat<(i32 (sextloadi8 I32:$addr)), (LOAD8_S_I32 0, $addr)>;
 def : Pat<(i32 (zextloadi8 I32:$addr)), (LOAD8_U_I32 0, $addr)>;
@@ -76,13 +134,189 @@
 def : Pat<(i64 (sextloadi32 I32:$addr)), (LOAD32_S_I64 0, $addr)>;
 def : Pat<(i64 (zextloadi32 I32:$addr)), (LOAD32_U_I64 0, $addr)>;
 
-// "Don't care" extending load become zero-extending load.
+// Select extending loads with a constant offset.
+def : Pat<(i32 (sextloadi8 (regPlusImm imm:$off, I32:$addr))),
+          (LOAD8_S_I32 imm:$off, $addr)>;
+def : Pat<(i32 (zextloadi8 (regPlusImm imm:$off, I32:$addr))),
+          (LOAD8_U_I32 imm:$off, $addr)>;
+def : Pat<(i32 (sextloadi16 (regPlusImm imm:$off, I32:$addr))),
+          (LOAD16_S_I32 imm:$off, $addr)>;
+def : Pat<(i32 (zextloadi16 (regPlusImm imm:$off, I32:$addr))),
+          (LOAD16_U_I32 imm:$off, $addr)>;
+def : Pat<(i64 (sextloadi8 (regPlusImm imm:$off, I32:$addr))),
+          (LOAD8_S_I64 imm:$off, $addr)>;
+def : Pat<(i64 (zextloadi8 (regPlusImm imm:$off, I32:$addr))),
+          (LOAD8_U_I64 imm:$off, $addr)>;
+def : Pat<(i64 (sextloadi16 (regPlusImm imm:$off, I32:$addr))),
+          (LOAD16_S_I64 imm:$off, $addr)>;
+def : Pat<(i64 (zextloadi16 (regPlusImm imm:$off, I32:$addr))),
+          (LOAD16_U_I64 imm:$off, $addr)>;
+def : Pat<(i64 (sextloadi32 (regPlusImm imm:$off, I32:$addr))),
+          (LOAD32_S_I64 imm:$off, $addr)>;
+def : Pat<(i64 (zextloadi32 (regPlusImm imm:$off, I32:$addr))),
+          (LOAD32_U_I64 imm:$off, $addr)>;
+def : Pat<(i32 (sextloadi8 (regPlusImm tglobaladdr:$off, I32:$addr))),
+          (LOAD8_S_I32 tglobaladdr:$off, $addr)>;
+def : Pat<(i32 (zextloadi8 (regPlusImm tglobaladdr:$off, I32:$addr))),
+          (LOAD8_U_I32 tglobaladdr:$off, $addr)>;
+def : Pat<(i32 (sextloadi16 (regPlusImm tglobaladdr:$off, I32:$addr))),
+          (LOAD16_S_I32 tglobaladdr:$off, $addr)>;
+def : Pat<(i32 (zextloadi16 (regPlusImm tglobaladdr:$off, I32:$addr))),
+          (LOAD16_U_I32 tglobaladdr:$off, $addr)>;
+def : Pat<(i64 (sextloadi8 (regPlusImm tglobaladdr:$off, I32:$addr))),
+          (LOAD8_S_I64 tglobaladdr:$off, $addr)>;
+def : Pat<(i64 (zextloadi8 (regPlusImm tglobaladdr:$off, I32:$addr))),
+          (LOAD8_U_I64 tglobaladdr:$off, $addr)>;
+def : Pat<(i64 (sextloadi16 (regPlusImm tglobaladdr:$off, I32:$addr))),
+          (LOAD16_S_I64 tglobaladdr:$off, $addr)>;
+def : Pat<(i64 (zextloadi16 (regPlusImm tglobaladdr:$off, I32:$addr))),
+          (LOAD16_U_I64 tglobaladdr:$off, $addr)>;
+def : Pat<(i64 (sextloadi32 (regPlusImm tglobaladdr:$off, I32:$addr))),
+          (LOAD32_S_I64 tglobaladdr:$off, $addr)>;
+def : Pat<(i64 (zextloadi32 (regPlusImm tglobaladdr:$off, I32:$addr))),
+          (LOAD32_U_I64 tglobaladdr:$off, $addr)>;
+def : Pat<(i32 (sextloadi8 (regPlusImm texternalsym:$off, I32:$addr))),
+          (LOAD8_S_I32 texternalsym:$off, $addr)>;
+def : Pat<(i32 (zextloadi8 (regPlusImm texternalsym:$off, I32:$addr))),
+          (LOAD8_U_I32 texternalsym:$off, $addr)>;
+def : Pat<(i32 (sextloadi16 (regPlusImm texternalsym:$off, I32:$addr))),
+          (LOAD16_S_I32 texternalsym:$off, $addr)>;
+def : Pat<(i32 (zextloadi16 (regPlusImm texternalsym:$off, I32:$addr))),
+          (LOAD16_U_I32 texternalsym:$off, $addr)>;
+def : Pat<(i64 (sextloadi8 (regPlusImm texternalsym:$off, I32:$addr))),
+          (LOAD8_S_I64 texternalsym:$off, $addr)>;
+def : Pat<(i64 (zextloadi8 (regPlusImm texternalsym:$off, I32:$addr))),
+          (LOAD8_U_I64 texternalsym:$off, $addr)>;
+def : Pat<(i64 (sextloadi16 (regPlusImm texternalsym:$off, I32:$addr))),
+          (LOAD16_S_I64 texternalsym:$off, $addr)>;
+def : Pat<(i64 (zextloadi16 (regPlusImm texternalsym:$off, I32:$addr))),
+          (LOAD16_U_I64 texternalsym:$off, $addr)>;
+def : Pat<(i64 (sextloadi32 (regPlusImm texternalsym:$off, I32:$addr))),
+          (LOAD32_S_I64 texternalsym:$off, $addr)>;
+def : Pat<(i64 (zextloadi32 (regPlusImm texternalsym:$off, I32:$addr))),
+          (LOAD32_U_I64 texternalsym:$off, $addr)>;
+
+// Select extending loads with just a constant offset.
+def : Pat<(i32 (sextloadi8 imm:$off)), (LOAD8_S_I32 imm:$off, (CONST_I32 0))>;
+def : Pat<(i32 (zextloadi8 imm:$off)), (LOAD8_U_I32 imm:$off, (CONST_I32 0))>;
+def : Pat<(i32 (sextloadi16 imm:$off)), (LOAD16_S_I32 imm:$off, (CONST_I32 0))>;
+def : Pat<(i32 (zextloadi16 imm:$off)), (LOAD16_U_I32 imm:$off, (CONST_I32 0))>;
+def : Pat<(i64 (sextloadi8 imm:$off)), (LOAD8_S_I64 imm:$off, (CONST_I32 0))>;
+def : Pat<(i64 (zextloadi8 imm:$off)), (LOAD8_U_I64 imm:$off, (CONST_I32 0))>;
+def : Pat<(i64 (sextloadi16 imm:$off)), (LOAD16_S_I64 imm:$off, (CONST_I32 0))>;
+def : Pat<(i64 (zextloadi16 imm:$off)), (LOAD16_U_I64 imm:$off, (CONST_I32 0))>;
+def : Pat<(i64 (sextloadi32 imm:$off)), (LOAD32_S_I64 imm:$off, (CONST_I32 0))>;
+def : Pat<(i64 (zextloadi32 imm:$off)), (LOAD32_U_I64 imm:$off, (CONST_I32 0))>;
+def : Pat<(i32 (sextloadi8 (WebAssemblywrapper tglobaladdr:$off))),
+          (LOAD8_S_I32 tglobaladdr:$off, (CONST_I32 0))>;
+def : Pat<(i32 (zextloadi8 (WebAssemblywrapper tglobaladdr:$off))),
+          (LOAD8_U_I32 tglobaladdr:$off, (CONST_I32 0))>;
+def : Pat<(i32 (sextloadi16 (WebAssemblywrapper tglobaladdr:$off))),
+          (LOAD16_S_I32 tglobaladdr:$off, (CONST_I32 0))>;
+def : Pat<(i32 (zextloadi16 (WebAssemblywrapper tglobaladdr:$off))),
+          (LOAD16_U_I32 tglobaladdr:$off, (CONST_I32 0))>;
+def : Pat<(i64 (sextloadi8 (WebAssemblywrapper tglobaladdr:$off))),
+          (LOAD8_S_I64 tglobaladdr:$off, (CONST_I32 0))>;
+def : Pat<(i64 (zextloadi8 (WebAssemblywrapper tglobaladdr:$off))),
+          (LOAD8_U_I64 tglobaladdr:$off, (CONST_I32 0))>;
+def : Pat<(i64 (sextloadi16 (WebAssemblywrapper tglobaladdr:$off))),
+          (LOAD16_S_I64 tglobaladdr:$off, (CONST_I32 0))>;
+def : Pat<(i64 (zextloadi16 (WebAssemblywrapper tglobaladdr:$off))),
+          (LOAD16_U_I64 tglobaladdr:$off, (CONST_I32 0))>;
+def : Pat<(i64 (sextloadi32 (WebAssemblywrapper tglobaladdr:$off))),
+          (LOAD32_S_I64 tglobaladdr:$off, (CONST_I32 0))>;
+def : Pat<(i64 (zextloadi32 (WebAssemblywrapper tglobaladdr:$off))),
+          (LOAD32_U_I64 tglobaladdr:$off, (CONST_I32 0))>;
+def : Pat<(i32 (sextloadi8 (WebAssemblywrapper texternalsym:$off))),
+          (LOAD8_S_I32 texternalsym:$off, (CONST_I32 0))>;
+def : Pat<(i32 (zextloadi8 (WebAssemblywrapper texternalsym:$off))),
+          (LOAD8_U_I32 texternalsym:$off, (CONST_I32 0))>;
+def : Pat<(i32 (sextloadi16 (WebAssemblywrapper texternalsym:$off))),
+          (LOAD16_S_I32 texternalsym:$off, (CONST_I32 0))>;
+def : Pat<(i32 (zextloadi16 (WebAssemblywrapper texternalsym:$off))),
+          (LOAD16_U_I32 texternalsym:$off, (CONST_I32 0))>;
+def : Pat<(i64 (sextloadi8 (WebAssemblywrapper texternalsym:$off))),
+          (LOAD8_S_I64 texternalsym:$off, (CONST_I32 0))>;
+def : Pat<(i64 (zextloadi8 (WebAssemblywrapper texternalsym:$off))),
+          (LOAD8_U_I64 texternalsym:$off, (CONST_I32 0))>;
+def : Pat<(i64 (sextloadi16 (WebAssemblywrapper texternalsym:$off))),
+          (LOAD16_S_I64 texternalsym:$off, (CONST_I32 0))>;
+def : Pat<(i64 (zextloadi16 (WebAssemblywrapper texternalsym:$off))),
+          (LOAD16_U_I64 texternalsym:$off, (CONST_I32 0))>;
+def : Pat<(i64 (sextloadi32 (WebAssemblywrapper texternalsym:$off))),
+          (LOAD32_S_I64 texternalsym:$off, (CONST_I32 0))>;
+def : Pat<(i64 (zextloadi32 (WebAssemblywrapper texternalsym:$off))),
+          (LOAD32_U_I64 texternalsym:$off, (CONST_I32 0))>;
+
+// Resolve "don't care" extending loads to zero-extending loads. This is
+// somewhat arbitrary, but zero-extending is conceptually simpler.
+
+// Select "don't care" extending loads with no constant offset.
 def : Pat<(i32 (extloadi8 I32:$addr)),  (LOAD8_U_I32 0, $addr)>;
 def : Pat<(i32 (extloadi16 I32:$addr)), (LOAD16_U_I32 0, $addr)>;
 def : Pat<(i64 (extloadi8 I32:$addr)),  (LOAD8_U_I64 0, $addr)>;
 def : Pat<(i64 (extloadi16 I32:$addr)), (LOAD16_U_I64 0, $addr)>;
 def : Pat<(i64 (extloadi32 I32:$addr)), (LOAD32_U_I64 0, $addr)>;
 
+// Select "don't care" extending loads with a constant offset.
+def : Pat<(i32 (extloadi8 (regPlusImm imm:$off, I32:$addr))),
+          (LOAD8_U_I32 imm:$off, $addr)>;
+def : Pat<(i32 (extloadi16 (regPlusImm imm:$off, I32:$addr))),
+          (LOAD16_U_I32 imm:$off, $addr)>;
+def : Pat<(i64 (extloadi8 (regPlusImm imm:$off, I32:$addr))),
+          (LOAD8_U_I64 imm:$off, $addr)>;
+def : Pat<(i64 (extloadi16 (regPlusImm imm:$off, I32:$addr))),
+          (LOAD16_U_I64 imm:$off, $addr)>;
+def : Pat<(i64 (extloadi32 (regPlusImm imm:$off, I32:$addr))),
+          (LOAD32_U_I64 imm:$off, $addr)>;
+def : Pat<(i32 (extloadi8 (regPlusImm tglobaladdr:$off, I32:$addr))),
+          (LOAD8_U_I32 tglobaladdr:$off, $addr)>;
+def : Pat<(i32 (extloadi16 (regPlusImm tglobaladdr:$off, I32:$addr))),
+          (LOAD16_U_I32 tglobaladdr:$off, $addr)>;
+def : Pat<(i64 (extloadi8 (regPlusImm tglobaladdr:$off, I32:$addr))),
+          (LOAD8_U_I64 tglobaladdr:$off, $addr)>;
+def : Pat<(i64 (extloadi16 (regPlusImm tglobaladdr:$off, I32:$addr))),
+          (LOAD16_U_I64 tglobaladdr:$off, $addr)>;
+def : Pat<(i64 (extloadi32 (regPlusImm tglobaladdr:$off, I32:$addr))),
+          (LOAD32_U_I64 tglobaladdr:$off, $addr)>;
+def : Pat<(i32 (extloadi8 (regPlusImm texternalsym:$off, I32:$addr))),
+          (LOAD8_U_I32 texternalsym:$off, $addr)>;
+def : Pat<(i32 (extloadi16 (regPlusImm texternalsym:$off, I32:$addr))),
+          (LOAD16_U_I32 texternalsym:$off, $addr)>;
+def : Pat<(i64 (extloadi8 (regPlusImm texternalsym:$off, I32:$addr))),
+          (LOAD8_U_I64 texternalsym:$off, $addr)>;
+def : Pat<(i64 (extloadi16 (regPlusImm texternalsym:$off, I32:$addr))),
+          (LOAD16_U_I64 texternalsym:$off, $addr)>;
+def : Pat<(i64 (extloadi32 (regPlusImm texternalsym:$off, I32:$addr))),
+          (LOAD32_U_I64 texternalsym:$off, $addr)>;
+
+// Select "don't care" extending loads with just a constant offset.
+def : Pat<(i32 (extloadi8 imm:$off)), (LOAD8_U_I32 imm:$off, (CONST_I32 0))>;
+def : Pat<(i32 (extloadi16 imm:$off)), (LOAD16_U_I32 imm:$off, (CONST_I32 0))>;
+def : Pat<(i64 (extloadi8 imm:$off)), (LOAD8_U_I64 imm:$off, (CONST_I32 0))>;
+def : Pat<(i64 (extloadi16 imm:$off)), (LOAD16_U_I64 imm:$off, (CONST_I32 0))>;
+def : Pat<(i64 (extloadi32 imm:$off)), (LOAD32_U_I64 imm:$off, (CONST_I32 0))>;
+def : Pat<(i32 (extloadi8 (WebAssemblywrapper tglobaladdr:$off))),
+          (LOAD8_U_I32 tglobaladdr:$off, (CONST_I32 0))>;
+def : Pat<(i32 (extloadi16 (WebAssemblywrapper tglobaladdr:$off))),
+          (LOAD16_U_I32 tglobaladdr:$off, (CONST_I32 0))>;
+def : Pat<(i64 (extloadi8 (WebAssemblywrapper tglobaladdr:$off))),
+          (LOAD8_U_I64 tglobaladdr:$off, (CONST_I32 0))>;
+def : Pat<(i64 (extloadi16 (WebAssemblywrapper tglobaladdr:$off))),
+          (LOAD16_U_I64 tglobaladdr:$off, (CONST_I32 0))>;
+def : Pat<(i64 (extloadi32 (WebAssemblywrapper tglobaladdr:$off))),
+          (LOAD32_U_I64 tglobaladdr:$off, (CONST_I32 0))>;
+def : Pat<(i32 (extloadi8 (WebAssemblywrapper texternalsym:$off))),
+          (LOAD8_U_I32 texternalsym:$off, (CONST_I32 0))>;
+def : Pat<(i32 (extloadi16 (WebAssemblywrapper texternalsym:$off))),
+          (LOAD16_U_I32 texternalsym:$off, (CONST_I32 0))>;
+def : Pat<(i64 (extloadi8 (WebAssemblywrapper texternalsym:$off))),
+          (LOAD8_U_I64 texternalsym:$off, (CONST_I32 0))>;
+def : Pat<(i64 (extloadi16 (WebAssemblywrapper texternalsym:$off))),
+          (LOAD16_U_I64 texternalsym:$off, (CONST_I32 0))>;
+def : Pat<(i64 (extloadi32 (WebAssemblywrapper texternalsym:$off))),
+          (LOAD32_U_I64 tglobaladdr:$off, (CONST_I32 0))>;
+
 let Defs = [ARGUMENTS] in {
 
 // Basic store.
@@ -102,17 +336,63 @@
 
 } // Defs = [ARGUMENTS]
 
+// Select stores with no constant offset.
 def : Pat<(store I32:$val, I32:$addr), (STORE_I32 0, I32:$addr, I32:$val)>;
 def : Pat<(store I64:$val, I32:$addr), (STORE_I64 0, I32:$addr, I64:$val)>;
 def : Pat<(store F32:$val, I32:$addr), (STORE_F32 0, I32:$addr, F32:$val)>;
 def : Pat<(store F64:$val, I32:$addr), (STORE_F64 0, I32:$addr, F64:$val)>;
 
-// FIXME: This pattern matches an immediate to actually use the offset field
-// in the store instruction; however only unsigned offsets are supported in
-// wasm, so we need to constrain the immediate we match. This may require
-// custom code rather than a simple pattern.
-// def : Pat<(store I32:$val, (add I32:$addr, (i32 imm:$off))),
-//           (STORE_I32 imm:$off, I32:$addr, I32:$val)>;
+// Select stores with a constant offset.
+def : Pat<(store I32:$val, (regPlusImm imm:$off, I32:$addr)),
+          (STORE_I32 imm:$off, I32:$addr, I32:$val)>;
+def : Pat<(store I64:$val, (regPlusImm imm:$off, I32:$addr)),
+          (STORE_I64 imm:$off, I32:$addr, I64:$val)>;
+def : Pat<(store F32:$val, (regPlusImm imm:$off, I32:$addr)),
+          (STORE_F32 imm:$off, I32:$addr, F32:$val)>;
+def : Pat<(store F64:$val, (regPlusImm imm:$off, I32:$addr)),
+          (STORE_F64 imm:$off, I32:$addr, F64:$val)>;
+def : Pat<(store I32:$val, (regPlusImm tglobaladdr:$off, I32:$addr)),
+          (STORE_I32 tglobaladdr:$off, I32:$addr, I32:$val)>;
+def : Pat<(store I64:$val, (regPlusImm tglobaladdr:$off, I32:$addr)),
+          (STORE_I64 tglobaladdr:$off, I32:$addr, I64:$val)>;
+def : Pat<(store F32:$val, (regPlusImm tglobaladdr:$off, I32:$addr)),
+          (STORE_F32 tglobaladdr:$off, I32:$addr, F32:$val)>;
+def : Pat<(store F64:$val, (regPlusImm tglobaladdr:$off, I32:$addr)),
+          (STORE_F64 tglobaladdr:$off, I32:$addr, F64:$val)>;
+def : Pat<(store I32:$val, (regPlusImm texternalsym:$off, I32:$addr)),
+          (STORE_I32 texternalsym:$off, I32:$addr, I32:$val)>;
+def : Pat<(store I64:$val, (regPlusImm texternalsym:$off, I32:$addr)),
+          (STORE_I64 texternalsym:$off, I32:$addr, I64:$val)>;
+def : Pat<(store F32:$val, (regPlusImm texternalsym:$off, I32:$addr)),
+          (STORE_F32 texternalsym:$off, I32:$addr, F32:$val)>;
+def : Pat<(store F64:$val, (regPlusImm texternalsym:$off, I32:$addr)),
+          (STORE_F64 texternalsym:$off, I32:$addr, F64:$val)>;
+
+// Select stores with just a constant offset.
+def : Pat<(store I32:$val, imm:$off),
+          (STORE_I32 imm:$off, (CONST_I32 0), I32:$val)>;
+def : Pat<(store I64:$val, imm:$off),
+          (STORE_I64 imm:$off, (CONST_I32 0), I64:$val)>;
+def : Pat<(store F32:$val, imm:$off),
+          (STORE_F32 imm:$off, (CONST_I32 0), F32:$val)>;
+def : Pat<(store F64:$val, imm:$off),
+          (STORE_F64 imm:$off, (CONST_I32 0), F64:$val)>;
+def : Pat<(store I32:$val, (WebAssemblywrapper tglobaladdr:$off)),
+          (STORE_I32 tglobaladdr:$off, (CONST_I32 0), I32:$val)>;
+def : Pat<(store I64:$val, (WebAssemblywrapper tglobaladdr:$off)),
+          (STORE_I64 tglobaladdr:$off, (CONST_I32 0), I64:$val)>;
+def : Pat<(store F32:$val, (WebAssemblywrapper tglobaladdr:$off)),
+          (STORE_F32 tglobaladdr:$off, (CONST_I32 0), F32:$val)>;
+def : Pat<(store F64:$val, (WebAssemblywrapper tglobaladdr:$off)),
+          (STORE_F64 tglobaladdr:$off, (CONST_I32 0), F64:$val)>;
+def : Pat<(store I32:$val, (WebAssemblywrapper texternalsym:$off)),
+          (STORE_I32 texternalsym:$off, (CONST_I32 0), I32:$val)>;
+def : Pat<(store I64:$val, (WebAssemblywrapper texternalsym:$off)),
+          (STORE_I64 texternalsym:$off, (CONST_I32 0), I64:$val)>;
+def : Pat<(store F32:$val, (WebAssemblywrapper texternalsym:$off)),
+          (STORE_F32 texternalsym:$off, (CONST_I32 0), F32:$val)>;
+def : Pat<(store F64:$val, (WebAssemblywrapper texternalsym:$off)),
+          (STORE_F64 texternalsym:$off, (CONST_I32 0), F64:$val)>;
 
 let Defs = [ARGUMENTS] in {
 
@@ -130,6 +410,7 @@
 
 } // Defs = [ARGUMENTS]
 
+// Select truncating stores with no constant offset.
 def : Pat<(truncstorei8 I32:$val, I32:$addr),
           (STORE8_I32 0, I32:$addr, I32:$val)>;
 def : Pat<(truncstorei16 I32:$val, I32:$addr),
@@ -141,6 +422,70 @@
 def : Pat<(truncstorei32 I64:$val, I32:$addr),
           (STORE32_I64 0, I32:$addr, I64:$val)>;
 
+// Select truncating stores with a constant offset.
+def : Pat<(truncstorei8 I32:$val, (regPlusImm imm:$off, I32:$addr)),
+          (STORE8_I32 imm:$off, I32:$addr, I32:$val)>;
+def : Pat<(truncstorei16 I32:$val, (regPlusImm imm:$off, I32:$addr)),
+          (STORE16_I32 imm:$off, I32:$addr, I32:$val)>;
+def : Pat<(truncstorei8 I64:$val, (regPlusImm imm:$off, I32:$addr)),
+          (STORE8_I64 imm:$off, I32:$addr, I64:$val)>;
+def : Pat<(truncstorei16 I64:$val, (regPlusImm imm:$off, I32:$addr)),
+          (STORE16_I64 imm:$off, I32:$addr, I64:$val)>;
+def : Pat<(truncstorei32 I64:$val, (regPlusImm imm:$off, I32:$addr)),
+          (STORE32_I64 imm:$off, I32:$addr, I64:$val)>;
+def : Pat<(truncstorei8 I32:$val, (regPlusImm tglobaladdr:$off, I32:$addr)),
+          (STORE8_I32 tglobaladdr:$off, I32:$addr, I32:$val)>;
+def : Pat<(truncstorei16 I32:$val, (regPlusImm tglobaladdr:$off, I32:$addr)),
+          (STORE16_I32 tglobaladdr:$off, I32:$addr, I32:$val)>;
+def : Pat<(truncstorei8 I64:$val, (regPlusImm tglobaladdr:$off, I32:$addr)),
+          (STORE8_I64 tglobaladdr:$off, I32:$addr, I64:$val)>;
+def : Pat<(truncstorei16 I64:$val, (regPlusImm tglobaladdr:$off, I32:$addr)),
+          (STORE16_I64 tglobaladdr:$off, I32:$addr, I64:$val)>;
+def : Pat<(truncstorei32 I64:$val, (regPlusImm tglobaladdr:$off, I32:$addr)),
+          (STORE32_I64 tglobaladdr:$off, I32:$addr, I64:$val)>;
+def : Pat<(truncstorei8 I32:$val, (regPlusImm texternalsym:$off, I32:$addr)),
+          (STORE8_I32 texternalsym:$off, I32:$addr, I32:$val)>;
+def : Pat<(truncstorei16 I32:$val, (regPlusImm texternalsym:$off, I32:$addr)),
+          (STORE16_I32 texternalsym:$off, I32:$addr, I32:$val)>;
+def : Pat<(truncstorei8 I64:$val, (regPlusImm texternalsym:$off, I32:$addr)),
+          (STORE8_I64 texternalsym:$off, I32:$addr, I64:$val)>;
+def : Pat<(truncstorei16 I64:$val, (regPlusImm texternalsym:$off, I32:$addr)),
+          (STORE16_I64 texternalsym:$off, I32:$addr, I64:$val)>;
+def : Pat<(truncstorei32 I64:$val, (regPlusImm texternalsym:$off, I32:$addr)),
+          (STORE32_I64 texternalsym:$off, I32:$addr, I64:$val)>;
+
+// Select truncating stores with just a constant offset.
+def : Pat<(truncstorei8 I32:$val, imm:$off),
+          (STORE8_I32 imm:$off, (CONST_I32 0), I32:$val)>;
+def : Pat<(truncstorei16 I32:$val, imm:$off),
+          (STORE16_I32 imm:$off, (CONST_I32 0), I32:$val)>;
+def : Pat<(truncstorei8 I64:$val, imm:$off),
+          (STORE8_I64 imm:$off, (CONST_I32 0), I64:$val)>;
+def : Pat<(truncstorei16 I64:$val, imm:$off),
+          (STORE16_I64 imm:$off, (CONST_I32 0), I64:$val)>;
+def : Pat<(truncstorei32 I64:$val, imm:$off),
+          (STORE32_I64 imm:$off, (CONST_I32 0), I64:$val)>;
+def : Pat<(truncstorei8 I32:$val, (WebAssemblywrapper tglobaladdr:$off)),
+          (STORE8_I32 tglobaladdr:$off, (CONST_I32 0), I32:$val)>;
+def : Pat<(truncstorei16 I32:$val, (WebAssemblywrapper tglobaladdr:$off)),
+          (STORE16_I32 tglobaladdr:$off, (CONST_I32 0), I32:$val)>;
+def : Pat<(truncstorei8 I64:$val, (WebAssemblywrapper tglobaladdr:$off)),
+          (STORE8_I64 tglobaladdr:$off, (CONST_I32 0), I64:$val)>;
+def : Pat<(truncstorei16 I64:$val, (WebAssemblywrapper tglobaladdr:$off)),
+          (STORE16_I64 tglobaladdr:$off, (CONST_I32 0), I64:$val)>;
+def : Pat<(truncstorei32 I64:$val, (WebAssemblywrapper tglobaladdr:$off)),
+          (STORE32_I64 tglobaladdr:$off, (CONST_I32 0), I64:$val)>;
+def : Pat<(truncstorei8 I32:$val, (WebAssemblywrapper texternalsym:$off)),
+          (STORE8_I32 texternalsym:$off, (CONST_I32 0), I32:$val)>;
+def : Pat<(truncstorei16 I32:$val, (WebAssemblywrapper texternalsym:$off)),
+          (STORE16_I32 texternalsym:$off, (CONST_I32 0), I32:$val)>;
+def : Pat<(truncstorei8 I64:$val, (WebAssemblywrapper texternalsym:$off)),
+          (STORE8_I64 texternalsym:$off, (CONST_I32 0), I64:$val)>;
+def : Pat<(truncstorei16 I64:$val, (WebAssemblywrapper texternalsym:$off)),
+          (STORE16_I64 texternalsym:$off, (CONST_I32 0), I64:$val)>;
+def : Pat<(truncstorei32 I64:$val, (WebAssemblywrapper texternalsym:$off)),
+          (STORE32_I64 texternalsym:$off, (CONST_I32 0), I64:$val)>;
+
 let Defs = [ARGUMENTS] in {
 
 // Memory size.
Index: test/CodeGen/WebAssembly/global.ll
===================================================================
--- test/CodeGen/WebAssembly/global.ll
+++ test/CodeGen/WebAssembly/global.ll
@@ -10,8 +10,8 @@
 @llvm.used = appending global [1 x i32*] [i32* @g], section "llvm.metadata"
 
 ; CHECK: foo:
-; CHECK: i32.const $push0=, answer{{$}}
-; CHECK-NEXT: i32.load $push1=, 0($pop0){{$}}
+; CHECK: i32.const $push0=, 0{{$}}
+; CHECK-NEXT: i32.load $push1=, answer($pop0){{$}}
 ; CHECK-NEXT: return $pop1{{$}}
 define i32 @foo() {
   %a = load i32, i32* @answer
Index: test/CodeGen/WebAssembly/offset.ll
===================================================================
--- test/CodeGen/WebAssembly/offset.ll
+++ test/CodeGen/WebAssembly/offset.ll
@@ -0,0 +1,147 @@
+; RUN: llc < %s -asm-verbose=false | FileCheck %s
+
+; Test constant load and store address offsets.
+
+target datalayout = "e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-unknown"
+
+; With an nuw add, we can fold an offset.
+
+; CHECK-LABEL: load_i32_with_folded_offset:
+; CHECK: i32.load  $push0=, 24($0){{$}}
+define i32 @load_i32_with_folded_offset(i32* %p) {
+  %q = ptrtoint i32* %p to i32
+  %r = add nuw i32 %q, 24
+  %s = inttoptr i32 %r to i32*
+  %t = load i32, i32* %s
+  ret i32 %t
+}
+
+; Without nuw, and even with nsw, we can't fold an offset.
+
+; CHECK-LABEL: load_i32_with_unfolded_offset:
+; CHECK: i32.const $push0=, 24{{$}}
+; CHECK: i32.add   $push1=, $0, $pop0{{$}}
+; CHECK: i32.load  $push2=, 0($pop1){{$}}
+define i32 @load_i32_with_unfolded_offset(i32* %p) {
+  %q = ptrtoint i32* %p to i32
+  %r = add nsw i32 %q, 24
+  %s = inttoptr i32 %r to i32*
+  %t = load i32, i32* %s
+  ret i32 %t
+}
+
+; Same as above but with i64.
+
+; CHECK-LABEL: load_i64_with_folded_offset:
+; CHECK: i64.load  $push0=, 24($0){{$}}
+define i64 @load_i64_with_folded_offset(i64* %p) {
+  %q = ptrtoint i64* %p to i32
+  %r = add nuw i32 %q, 24
+  %s = inttoptr i32 %r to i64*
+  %t = load i64, i64* %s
+  ret i64 %t
+}
+
+; Same as above but with i64.
+
+; CHECK-LABEL: load_i64_with_unfolded_offset:
+; CHECK: i32.const $push0=, 24{{$}}
+; CHECK: i32.add   $push1=, $0, $pop0{{$}}
+; CHECK: i64.load  $push2=, 0($pop1){{$}}
+define i64 @load_i64_with_unfolded_offset(i64* %p) {
+  %q = ptrtoint i64* %p to i32
+  %r = add nsw i32 %q, 24
+  %s = inttoptr i32 %r to i64*
+  %t = load i64, i64* %s
+  ret i64 %t
+}
+
+; Same as above but with store.
+
+; CHECK-LABEL: store_i32_with_folded_offset:
+; CHECK: i32.store $discard=, 24($0), $pop0{{$}}
+define void @store_i32_with_folded_offset(i32* %p) {
+  %q = ptrtoint i32* %p to i32
+  %r = add nuw i32 %q, 24
+  %s = inttoptr i32 %r to i32*
+  store i32 0, i32* %s
+  ret void
+}
+
+; Same as above but with store.
+
+; CHECK-LABEL: store_i32_with_unfolded_offset:
+; CHECK: i32.const $push0=, 24{{$}}
+; CHECK: i32.add   $push1=, $0, $pop0{{$}}
+; CHECK: i32.store $discard=, 0($pop1), $pop2{{$}}
+define void @store_i32_with_unfolded_offset(i32* %p) {
+  %q = ptrtoint i32* %p to i32
+  %r = add nsw i32 %q, 24
+  %s = inttoptr i32 %r to i32*
+  store i32 0, i32* %s
+  ret void
+}
+
+; Same as above but with store with i64.
+
+; CHECK-LABEL: store_i64_with_folded_offset:
+; CHECK: i64.store $discard=, 24($0), $pop0{{$}}
+define void @store_i64_with_folded_offset(i64* %p) {
+  %q = ptrtoint i64* %p to i32
+  %r = add nuw i32 %q, 24
+  %s = inttoptr i32 %r to i64*
+  store i64 0, i64* %s
+  ret void
+}
+
+; Same as above but with store with i64.
+
+; CHECK-LABEL: store_i64_with_unfolded_offset:
+; CHECK: i32.const $push0=, 24{{$}}
+; CHECK: i32.add   $push1=, $0, $pop0{{$}}
+; CHECK: i64.store $discard=, 0($pop1), $pop2{{$}}
+define void @store_i64_with_unfolded_offset(i64* %p) {
+  %q = ptrtoint i64* %p to i32
+  %r = add nsw i32 %q, 24
+  %s = inttoptr i32 %r to i64*
+  store i64 0, i64* %s
+  ret void
+}
+
+; When loading from a fixed address, materialize a zero.
+
+; CHECK-LABEL: load_i32_from_numeric_address
+; CHECK: i32.const $push0=, 0{{$}}
+; CHECK: i32.load  $push1=, 42($pop0){{$}}
+define i32 @load_i32_from_numeric_address() {
+  %s = inttoptr i32 42 to i32*
+  %t = load i32, i32* %s
+  ret i32 %t
+}
+
+; CHECK-LABEL: load_i32_from_global_address
+; CHECK: i32.const $push0=, 0{{$}}
+; CHECK: i32.load  $push1=, gv($pop0){{$}}
+@gv = global i32 0
+define i32 @load_i32_from_global_address() {
+  %t = load i32, i32* @gv
+  ret i32 %t
+}
+
+; CHECK-LABEL: store_i32_to_numeric_address:
+; CHECK: i32.const $0=, 0{{$}}
+; CHECK: i32.store $discard=, 42($0), $0{{$}}
+define void @store_i32_to_numeric_address() {
+  %s = inttoptr i32 42 to i32*
+  store i32 0, i32* %s
+  ret void
+}
+
+; CHECK-LABEL: store_i32_to_global_address:
+; CHECK: i32.const $0=, 0{{$}}
+; CHECK: i32.store $discard=, gv($0), $0{{$}}
+define void @store_i32_to_global_address() {
+  store i32 0, i32* @gv
+  ret void
+}
Index: test/CodeGen/WebAssembly/store-results.ll
===================================================================
--- test/CodeGen/WebAssembly/store-results.ll
+++ test/CodeGen/WebAssembly/store-results.ll
@@ -26,7 +26,7 @@
 @pos = global %class.Vec3 zeroinitializer, align 4
 
 ; CHECK-LABEL: foo:
-; CHECK: i32.store $discard=, 0($pop0), $0{{$}}
+; CHECK: i32.store $discard=, pos($0), $0{{$}}
 define void @foo() {
 for.body.i:
   br label %for.body5.i
@@ -44,7 +44,7 @@
 }
 
 ; CHECK-LABEL: bar:
-; CHECK: i32.store $discard=, 0($0), $pop0{{$}}
+; CHECK: i32.store $discard=, pos($0), $0{{$}}
 define void @bar() {
 for.body.i:
   br label %for.body5.i