V_SET0 has no side effects.

TableGen will mark any pattern-less instruction as having unmodeled side
effects. This is extra bad for V_SET0 which gets rematerialized a lot.

This was part of the cause for PR11125, but the real bug was fixed
in r141923.

llvm-svn: 141924

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/Target/X86/X86InstrSSE.td b/llvm/lib/Target/X86/X86InstrSSE.td
index 520de683f10..d3ced23450f 100644
--- a/llvm/lib/Target/X86/X86InstrSSE.td
+++ b/llvm/lib/Target/X86/X86InstrSSE.td
@@ -266,7 +266,7 @@ let isReMaterializable = 1, isAsCheapAsAMove = 1, isCodeGenOnly = 1,
 // We set canFoldAsLoad because this can be converted to a constant-pool
 // load of an all-zeros value if folding it would be beneficial.
 let isReMaterializable = 1, isAsCheapAsAMove = 1, canFoldAsLoad = 1,
-    isPseudo = 1 in {
+    isPseudo = 1, neverHasSideEffects = 1 in {
 def V_SET0 : I<0, Pseudo, (outs VR128:$dst), (ins), "", []>;
 }