Index: llvm/trunk/lib/Target/X86/X86.td
===================================================================
--- llvm/trunk/lib/Target/X86/X86.td
+++ llvm/trunk/lib/Target/X86/X86.td
@@ -427,6 +427,11 @@
         "Prefer horizontal vector math instructions (haddp, phsub, etc.) over "
         "normal vector instructions with shuffles", [FeatureSSE3]>;
 
+def FeatureFastScalarShiftMasks
+    : SubtargetFeature<
+        "fast-scalar-shift-masks", "HasFastScalarShiftMasks", "true",
+        "Prefer a left/right scalar logical shift pair over a shift+and pair">;
+
 def FeatureFastVectorShiftMasks
     : SubtargetFeature<
         "fast-vector-shift-masks", "HasFastVectorShiftMasks", "true",
@@ -784,6 +789,7 @@
                                                       FeatureSlowSHLD,
                                                       FeatureLAHFSAHF,
                                                       FeatureFast15ByteNOP,
+                                                      FeatureFastScalarShiftMasks,
                                                       FeatureFastVectorShiftMasks];
   list<SubtargetFeature> BtVer1Features = BtVer1InheritableFeatures;
 
@@ -825,6 +831,7 @@
                                                       FeatureSlowSHLD,
                                                       FeatureLAHFSAHF,
                                                       FeatureFast11ByteNOP,
+                                                      FeatureFastScalarShiftMasks,
                                                       FeatureBranchFusion];
   list<SubtargetFeature> BdVer1Features = BdVer1InheritableFeatures;
 
@@ -876,6 +883,7 @@
                                        FeatureFastBEXTR,
                                        FeatureFast15ByteNOP,
                                        FeatureBranchFusion,
+                                       FeatureFastScalarShiftMasks,
                                        FeatureMMX,
                                        FeatureMOVBE,
                                        FeatureMWAITX,
@@ -1092,20 +1100,22 @@
 foreach P = ["k8", "opteron", "athlon64", "athlon-fx"] in {
   def : Proc<P, [FeatureX87, FeatureSlowUAMem16, FeatureCMPXCHG8B,
                  FeatureSSE2, Feature3DNowA, FeatureFXSR, FeatureNOPL,
-                 Feature64Bit, FeatureSlowSHLD, FeatureCMOV]>;
+                 Feature64Bit, FeatureSlowSHLD, FeatureCMOV,
+                 FeatureFastScalarShiftMasks]>;
 }
 
 foreach P = ["k8-sse3", "opteron-sse3", "athlon64-sse3"] in {
   def : Proc<P, [FeatureX87, FeatureSlowUAMem16, FeatureCMPXCHG8B, FeatureSSE3,
                  Feature3DNowA, FeatureFXSR, FeatureNOPL, FeatureCMPXCHG16B,
-                 FeatureSlowSHLD, FeatureCMOV, Feature64Bit]>;
+                 FeatureSlowSHLD, FeatureCMOV, Feature64Bit,
+                 FeatureFastScalarShiftMasks]>;
 }
 
 foreach P = ["amdfam10", "barcelona"] in {
   def : Proc<P, [FeatureX87, FeatureCMPXCHG8B, FeatureSSE4A, Feature3DNowA,
                  FeatureFXSR, FeatureNOPL, FeatureCMPXCHG16B, FeatureLZCNT,
                  FeaturePOPCNT, FeatureSlowSHLD, FeatureLAHFSAHF, FeatureCMOV,
-                 Feature64Bit]>;
+                 Feature64Bit, FeatureFastScalarShiftMasks]>;
 }
 
 // Bobcat
Index: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
===================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
@@ -5021,11 +5021,12 @@
           (N->getOpcode() == ISD::SRL &&
            N->getOperand(0).getOpcode() == ISD::SHL)) &&
          "Expected shift-shift mask");
-
-  if (Subtarget.hasFastVectorShiftMasks() && N->getValueType(0).isVector()) {
+  EVT VT = N->getValueType(0);
+  if ((Subtarget.hasFastVectorShiftMasks() && VT.isVector()) ||
+      (Subtarget.hasFastScalarShiftMasks() && !VT.isVector())) {
     // Only fold if the shift values are equal - so it folds to AND.
-    // TODO - we should fold if either is non-uniform but we don't do the
-    // fold for non-splats yet.
+    // TODO - we should fold if either is a non-uniform vector but we don't do
+    // the fold for non-splats yet.
     return N->getOperand(1) == N->getOperand(0).getOperand(1);
   }
   return TargetLoweringBase::shouldFoldConstantShiftPairToMask(N, Level);
Index: llvm/trunk/lib/Target/X86/X86Subtarget.h
===================================================================
--- llvm/trunk/lib/Target/X86/X86Subtarget.h
+++ llvm/trunk/lib/Target/X86/X86Subtarget.h
@@ -396,6 +396,9 @@
   /// Try harder to combine to horizontal vector ops if they are fast.
   bool HasFastHorizontalOps = false;
 
+  /// Prefer a left/right scalar logical shifts pair over a shift+and pair.
+  bool HasFastScalarShiftMasks = false;
+
   /// Prefer a left/right vector logical shifts pair over a shift+and pair.
   bool HasFastVectorShiftMasks = false;
 
@@ -650,6 +653,7 @@
   bool hasFastSHLDRotate() const { return HasFastSHLDRotate; }
   bool hasFastBEXTR() const { return HasFastBEXTR; }
   bool hasFastHorizontalOps() const { return HasFastHorizontalOps; }
+  bool hasFastScalarShiftMasks() const { return HasFastScalarShiftMasks; }
   bool hasFastVectorShiftMasks() const { return HasFastVectorShiftMasks; }
   bool hasMacroFusion() const { return HasMacroFusion; }
   bool hasBranchFusion() const { return HasBranchFusion; }
Index: llvm/trunk/test/CodeGen/X86/shift-mask.ll
===================================================================
--- llvm/trunk/test/CodeGen/X86/shift-mask.ll
+++ llvm/trunk/test/CodeGen/X86/shift-mask.ll
@@ -43,13 +43,21 @@
 ; X86-NEXT:    andb $-32, %al
 ; X86-NEXT:    retl
 ;
-; X64-LABEL: test_i8_shl_lshr_1:
-; X64:       # %bb.0:
-; X64-NEXT:    # kill: def $edi killed $edi def $rdi
-; X64-NEXT:    leal (,%rdi,4), %eax
-; X64-NEXT:    andb $-32, %al
-; X64-NEXT:    # kill: def $al killed $al killed $eax
-; X64-NEXT:    retq
+; X64-MASK-LABEL: test_i8_shl_lshr_1:
+; X64-MASK:       # %bb.0:
+; X64-MASK-NEXT:    # kill: def $edi killed $edi def $rdi
+; X64-MASK-NEXT:    leal (,%rdi,4), %eax
+; X64-MASK-NEXT:    andb $-32, %al
+; X64-MASK-NEXT:    # kill: def $al killed $al killed $eax
+; X64-MASK-NEXT:    retq
+;
+; X64-SHIFT-LABEL: test_i8_shl_lshr_1:
+; X64-SHIFT:       # %bb.0:
+; X64-SHIFT-NEXT:    movl %edi, %eax
+; X64-SHIFT-NEXT:    shrb $3, %al
+; X64-SHIFT-NEXT:    shlb $5, %al
+; X64-SHIFT-NEXT:    # kill: def $al killed $al killed $eax
+; X64-SHIFT-NEXT:    retq
   %1 = lshr i8 %a0, 3
   %2 = shl i8 %1, 5
   ret i8 %2
@@ -63,13 +71,21 @@
 ; X86-NEXT:    andb $56, %al
 ; X86-NEXT:    retl
 ;
-; X64-LABEL: test_i8_shl_lshr_2:
-; X64:       # %bb.0:
-; X64-NEXT:    movl %edi, %eax
-; X64-NEXT:    shrb $2, %al
-; X64-NEXT:    andb $56, %al
-; X64-NEXT:    # kill: def $al killed $al killed $eax
-; X64-NEXT:    retq
+; X64-MASK-LABEL: test_i8_shl_lshr_2:
+; X64-MASK:       # %bb.0:
+; X64-MASK-NEXT:    movl %edi, %eax
+; X64-MASK-NEXT:    shrb $2, %al
+; X64-MASK-NEXT:    andb $56, %al
+; X64-MASK-NEXT:    # kill: def $al killed $al killed $eax
+; X64-MASK-NEXT:    retq
+;
+; X64-SHIFT-LABEL: test_i8_shl_lshr_2:
+; X64-SHIFT:       # %bb.0:
+; X64-SHIFT-NEXT:    # kill: def $edi killed $edi def $rdi
+; X64-SHIFT-NEXT:    shrb $5, %dil
+; X64-SHIFT-NEXT:    leal (,%rdi,8), %eax
+; X64-SHIFT-NEXT:    # kill: def $al killed $al killed $eax
+; X64-SHIFT-NEXT:    retq
   %1 = lshr i8 %a0, 5
   %2 = shl i8 %1, 3
   ret i8 %2
@@ -103,13 +119,21 @@
 ; X86-NEXT:    # kill: def $ax killed $ax killed $eax
 ; X86-NEXT:    retl
 ;
-; X64-LABEL: test_i16_shl_lshr_1:
-; X64:       # %bb.0:
-; X64-NEXT:    # kill: def $edi killed $edi def $rdi
-; X64-NEXT:    leal (,%rdi,4), %eax
-; X64-NEXT:    andl $65504, %eax # imm = 0xFFE0
-; X64-NEXT:    # kill: def $ax killed $ax killed $eax
-; X64-NEXT:    retq
+; X64-MASK-LABEL: test_i16_shl_lshr_1:
+; X64-MASK:       # %bb.0:
+; X64-MASK-NEXT:    # kill: def $edi killed $edi def $rdi
+; X64-MASK-NEXT:    leal (,%rdi,4), %eax
+; X64-MASK-NEXT:    andl $65504, %eax # imm = 0xFFE0
+; X64-MASK-NEXT:    # kill: def $ax killed $ax killed $eax
+; X64-MASK-NEXT:    retq
+;
+; X64-SHIFT-LABEL: test_i16_shl_lshr_1:
+; X64-SHIFT:       # %bb.0:
+; X64-SHIFT-NEXT:    movzwl %di, %eax
+; X64-SHIFT-NEXT:    shrl $3, %eax
+; X64-SHIFT-NEXT:    shll $5, %eax
+; X64-SHIFT-NEXT:    # kill: def $ax killed $ax killed $eax
+; X64-SHIFT-NEXT:    retq
   %1 = lshr i16 %a0, 3
   %2 = shl i16 %1, 5
   ret i16 %2
@@ -124,13 +148,21 @@
 ; X86-NEXT:    # kill: def $ax killed $ax killed $eax
 ; X86-NEXT:    retl
 ;
-; X64-LABEL: test_i16_shl_lshr_2:
-; X64:       # %bb.0:
-; X64-NEXT:    movl %edi, %eax
-; X64-NEXT:    shrl $2, %eax
-; X64-NEXT:    andl $16376, %eax # imm = 0x3FF8
-; X64-NEXT:    # kill: def $ax killed $ax killed $eax
-; X64-NEXT:    retq
+; X64-MASK-LABEL: test_i16_shl_lshr_2:
+; X64-MASK:       # %bb.0:
+; X64-MASK-NEXT:    movl %edi, %eax
+; X64-MASK-NEXT:    shrl $2, %eax
+; X64-MASK-NEXT:    andl $16376, %eax # imm = 0x3FF8
+; X64-MASK-NEXT:    # kill: def $ax killed $ax killed $eax
+; X64-MASK-NEXT:    retq
+;
+; X64-SHIFT-LABEL: test_i16_shl_lshr_2:
+; X64-SHIFT:       # %bb.0:
+; X64-SHIFT-NEXT:    movzwl %di, %eax
+; X64-SHIFT-NEXT:    shrl $5, %eax
+; X64-SHIFT-NEXT:    shll $3, %eax
+; X64-SHIFT-NEXT:    # kill: def $ax killed $ax killed $eax
+; X64-SHIFT-NEXT:    retq
   %1 = lshr i16 %a0, 5
   %2 = shl i16 %1, 3
   ret i16 %2
@@ -161,12 +193,19 @@
 ; X86-NEXT:    andl $-32, %eax
 ; X86-NEXT:    retl
 ;
-; X64-LABEL: test_i32_shl_lshr_1:
-; X64:       # %bb.0:
-; X64-NEXT:    # kill: def $edi killed $edi def $rdi
-; X64-NEXT:    leal (,%rdi,4), %eax
-; X64-NEXT:    andl $-32, %eax
-; X64-NEXT:    retq
+; X64-MASK-LABEL: test_i32_shl_lshr_1:
+; X64-MASK:       # %bb.0:
+; X64-MASK-NEXT:    # kill: def $edi killed $edi def $rdi
+; X64-MASK-NEXT:    leal (,%rdi,4), %eax
+; X64-MASK-NEXT:    andl $-32, %eax
+; X64-MASK-NEXT:    retq
+;
+; X64-SHIFT-LABEL: test_i32_shl_lshr_1:
+; X64-SHIFT:       # %bb.0:
+; X64-SHIFT-NEXT:    movl %edi, %eax
+; X64-SHIFT-NEXT:    shrl $3, %eax
+; X64-SHIFT-NEXT:    shll $5, %eax
+; X64-SHIFT-NEXT:    retq
   %1 = lshr i32 %a0, 3
   %2 = shl i32 %1, 5
   ret i32 %2
@@ -180,12 +219,19 @@
 ; X86-NEXT:    andl $-8, %eax
 ; X86-NEXT:    retl
 ;
-; X64-LABEL: test_i32_shl_lshr_2:
-; X64:       # %bb.0:
-; X64-NEXT:    movl %edi, %eax
-; X64-NEXT:    shrl $2, %eax
-; X64-NEXT:    andl $-8, %eax
-; X64-NEXT:    retq
+; X64-MASK-LABEL: test_i32_shl_lshr_2:
+; X64-MASK:       # %bb.0:
+; X64-MASK-NEXT:    movl %edi, %eax
+; X64-MASK-NEXT:    shrl $2, %eax
+; X64-MASK-NEXT:    andl $-8, %eax
+; X64-MASK-NEXT:    retq
+;
+; X64-SHIFT-LABEL: test_i32_shl_lshr_2:
+; X64-SHIFT:       # %bb.0:
+; X64-SHIFT-NEXT:    # kill: def $edi killed $edi def $rdi
+; X64-SHIFT-NEXT:    shrl $5, %edi
+; X64-SHIFT-NEXT:    leal (,%rdi,8), %eax
+; X64-SHIFT-NEXT:    retq
   %1 = lshr i32 %a0, 5
   %2 = shl i32 %1, 3
   ret i32 %2
@@ -219,11 +265,18 @@
 ; X86-NEXT:    shldl $2, %ecx, %edx
 ; X86-NEXT:    retl
 ;
-; X64-LABEL: test_i64_shl_lshr_1:
-; X64:       # %bb.0:
-; X64-NEXT:    leaq (,%rdi,4), %rax
-; X64-NEXT:    andq $-32, %rax
-; X64-NEXT:    retq
+; X64-MASK-LABEL: test_i64_shl_lshr_1:
+; X64-MASK:       # %bb.0:
+; X64-MASK-NEXT:    leaq (,%rdi,4), %rax
+; X64-MASK-NEXT:    andq $-32, %rax
+; X64-MASK-NEXT:    retq
+;
+; X64-SHIFT-LABEL: test_i64_shl_lshr_1:
+; X64-SHIFT:       # %bb.0:
+; X64-SHIFT-NEXT:    movq %rdi, %rax
+; X64-SHIFT-NEXT:    shrq $3, %rax
+; X64-SHIFT-NEXT:    shlq $5, %rax
+; X64-SHIFT-NEXT:    retq
   %1 = lshr i64 %a0, 3
   %2 = shl i64 %1, 5
   ret i64 %2
@@ -239,12 +292,18 @@
 ; X86-NEXT:    shrl $2, %edx
 ; X86-NEXT:    retl
 ;
-; X64-LABEL: test_i64_shl_lshr_2:
-; X64:       # %bb.0:
-; X64-NEXT:    movq %rdi, %rax
-; X64-NEXT:    shrq $2, %rax
-; X64-NEXT:    andq $-8, %rax
-; X64-NEXT:    retq
+; X64-MASK-LABEL: test_i64_shl_lshr_2:
+; X64-MASK:       # %bb.0:
+; X64-MASK-NEXT:    movq %rdi, %rax
+; X64-MASK-NEXT:    shrq $2, %rax
+; X64-MASK-NEXT:    andq $-8, %rax
+; X64-MASK-NEXT:    retq
+;
+; X64-SHIFT-LABEL: test_i64_shl_lshr_2:
+; X64-SHIFT:       # %bb.0:
+; X64-SHIFT-NEXT:    shrq $5, %rdi
+; X64-SHIFT-NEXT:    leaq (,%rdi,8), %rax
+; X64-SHIFT-NEXT:    retq
   %1 = lshr i64 %a0, 5
   %2 = shl i64 %1, 3
   ret i64 %2