use SUBREG_TO_REG instead of INSERT_SUBREG, this way the code

generator can know the top bits are zero, not undefined.
Thanks to Dan for pointing this out.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75899 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/X86Instr64bit.td b/lib/Target/X86/X86Instr64bit.td
index dd6f984144f397d5066c0881077e6ea3229b43ea..c4b25fca2fc9ed2953a9a69ec1a76de7f1110b7a 100644 (file)
--- a/lib/Target/X86/X86Instr64bit.td
+++ b/lib/Target/X86/X86Instr64bit.td
@@ -1309,7 +1309,7 @@ def Int_CVTTSS2SI64rm: RSSI<0x2C, MRMSrcMem, (outs GR64:$dst), (ins f32mem:$src)
 // when we have a better way to specify isel priority.
 let AddedComplexity = 1 in
 def : Pat<(i64 0),
-          (INSERT_SUBREG (i64 (IMPLICIT_DEF)), (MOV32r0), x86_subreg_32bit)>;
+          (SUBREG_TO_REG (i64 0), (MOV32r0), x86_subreg_32bit)>;
 
 
 // Materialize i64 constant where top 32-bits are zero.