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Set trunc store action to Expand for all X86 targets. 

When compiling without SSE2, isTruncStoreLegal(F64, F32) would return Legal, whereas with SSE2 it would return Expand. And since the Target doesn't seem to actually handle a truncstore for double -> float, it would just output a store of a full double in the space for a float hence overwriting other bits on the stack.

Patch by Luqman Aden!

llvm-svn: 217410
This commit is contained in:
Bob Wilson 2014-09-09 01:13:36 +00:00
parent 4ce63c2a54
commit b3482af341
2 changed files with 22 additions and 2 deletions
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4
llvm/lib/Target/X86/X86ISelLowering.cpp
View File

@ -317,6 +317,8 @@ void X86TargetLowering::resetOperationActions() {
setTruncStoreAction(MVT::i32, MVT::i8 , Expand);
setTruncStoreAction(MVT::i16, MVT::i8, Expand);
setTruncStoreAction(MVT::f64, MVT::f32, Expand);
// SETOEQ and SETUNE require checking two conditions.
setCondCodeAction(ISD::SETOEQ, MVT::f32, Expand);
setCondCodeAction(ISD::SETOEQ, MVT::f64, Expand);
@ -1057,8 +1059,6 @@ void X86TargetLowering::resetOperationActions() {
AddPromotedToType (ISD::SELECT, VT, MVT::v2i64);
}
setTruncStoreAction(MVT::f64, MVT::f32, Expand);
// Custom lower v2i64 and v2f64 selects.
setOperationAction(ISD::LOAD, MVT::v2f64, Legal);
setOperationAction(ISD::LOAD, MVT::v2i64, Legal);

20
llvm/test/CodeGen/X86/dont-trunc-store-double-to-float.ll Normal file
View File

@ -0,0 +1,20 @@
; RUN: llc -march=x86 < %s | FileCheck %s
; CHECK-LABEL: @bar
; CHECK: movl $1074339512,
; CHECK: movl $1374389535,
; CHECK: movl $1078523331,
define void @bar() unnamed_addr {
entry-block:
%a = alloca double
%b = alloca float
store double 3.140000e+00, double* %a
%0 = load double* %a
%1 = fptrunc double %0 to float
store float %1, float* %b
ret void
}