Index: include/llvm/Target/Target.td
===================================================================
--- include/llvm/Target/Target.td
+++ include/llvm/Target/Target.td
@@ -878,12 +878,16 @@
 // Standard Pseudo Instructions.
 // This list must match TargetOpcodes.h and CodeGenTarget.cpp.
 // Only these instructions are allowed in the TargetOpcode namespace.
-let isCodeGenOnly = 1, isPseudo = 1, hasNoSchedulingInfo = 1,
-    Namespace = "TargetOpcode" in {
+// Ensure mayLoad and mayStore have a default value, so as not to break
+// targets that set guessInstructionProperties=0. Any local definition of
+// mayLoad/mayStore takes precedence over these default values.
+let mayLoad = 0, mayStore = 0, isCodeGenOnly = 1, isPseudo = 1,
+    hasNoSchedulingInfo = 1, Namespace = "TargetOpcode" in {
 def PHI : Instruction {
   let OutOperandList = (outs unknown:$dst);
   let InOperandList = (ins variable_ops);
   let AsmString = "PHINODE";
+  let hasSideEffects = 1;
 }
 def INLINEASM : Instruction {
   let OutOperandList = (outs);
@@ -896,6 +900,7 @@
   let InOperandList = (ins i32imm:$id);
   let AsmString = "";
   let hasCtrlDep = 1;
+  let hasSideEffects = 1;
   let isNotDuplicable = 1;
 }
 def EH_LABEL : Instruction {
@@ -903,6 +908,7 @@
   let InOperandList = (ins i32imm:$id);
   let AsmString = "";
   let hasCtrlDep = 1;
+  let hasSideEffects = 1;
   let isNotDuplicable = 1;
 }
 def GC_LABEL : Instruction {
@@ -910,6 +916,7 @@
   let InOperandList = (ins i32imm:$id);
   let AsmString = "";
   let hasCtrlDep = 1;
+  let hasSideEffects = 1;
   let isNotDuplicable = 1;
 }
 def ANNOTATION_LABEL : Instruction {
@@ -917,6 +924,7 @@
   let InOperandList = (ins i32imm:$id);
   let AsmString = "";
   let hasCtrlDep = 1;
+  let hasSideEffects = 1;
   let isNotDuplicable = 1;
 }
 def KILL : Instruction {
@@ -984,6 +992,7 @@
   let OutOperandList = (outs);
   let InOperandList = (ins variable_ops);
   let AsmString = "BUNDLE";
+  let hasSideEffects = 1;
 }
 def LIFETIME_START : Instruction {
   let OutOperandList = (outs);
@@ -1000,6 +1009,7 @@
 def STACKMAP : Instruction {
   let OutOperandList = (outs);
   let InOperandList = (ins i64imm:$id, i32imm:$nbytes, variable_ops);
+  let hasSideEffects = 1;
   let isCall = 1;
   let mayLoad = 1;
   let usesCustomInserter = 1;
@@ -1008,6 +1018,7 @@
   let OutOperandList = (outs unknown:$dst);
   let InOperandList = (ins i64imm:$id, i32imm:$nbytes, unknown:$callee,
                        i32imm:$nargs, i32imm:$cc, variable_ops);
+  let hasSideEffects = 1;
   let isCall = 1;
   let mayLoad = 1;
   let usesCustomInserter = 1;
@@ -1042,6 +1053,7 @@
   let OutOperandList = (outs unknown:$dst);
   let InOperandList = (ins variable_ops);
   let usesCustomInserter = 1;
+  let hasSideEffects = 1;
   let mayLoad = 1;
   let mayStore = 1;
   let isTerminator = 1;
Index: lib/Target/Lanai/Lanai.td
===================================================================
--- lib/Target/Lanai/Lanai.td
+++ lib/Target/Lanai/Lanai.td
@@ -22,7 +22,9 @@
 include "LanaiCallingConv.td"
 include "LanaiInstrInfo.td"
 
-def LanaiInstrInfo : InstrInfo;
+def LanaiInstrInfo : InstrInfo {
+  let guessInstructionProperties = 0;
+}
 
 //===----------------------------------------------------------------------===//
 // Lanai processors supported.