[llvm] r217410 - Set trunc store action to Expand for all X86 targets.

[Bob Wilson]

Author: bwilson
Date: Mon Sep  8 20:13:36 2014
New Revision: 217410

URL: http://llvm.org/viewvc/llvm-project?rev=217410&view=rev
Log:
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!

Added:
    llvm/trunk/test/CodeGen/X86/dont-trunc-store-double-to-float.ll
Modified:
    llvm/trunk/lib/Target/X86/X86ISelLowering.cpp

Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=217410&r1=217409&r2=217410&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Mon Sep  8 20:13:36 2014
@@ -317,6 +317,8 @@ void X86TargetLowering::resetOperationAc
   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::resetOperationAc
       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);

Added: llvm/trunk/test/CodeGen/X86/dont-trunc-store-double-to-float.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/dont-trunc-store-double-to-float.ll?rev=217410&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/dont-trunc-store-double-to-float.ll (added)
+++ llvm/trunk/test/CodeGen/X86/dont-trunc-store-double-to-float.ll Mon Sep  8 20:13:36 2014
@@ -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
+}