[llvm] r286231 - [AArch64] Fix incorrect CSEL node created

[Roger Ferrer Ibanez via llvm-commits]

Author: rogfer01
Date: Tue Nov  8 07:34:41 2016
New Revision: 286231

URL: http://llvm.org/viewvc/llvm-project?rev=286231&view=rev
Log:
[AArch64] Fix incorrect CSEL node created

Under -enable-unsafe-fp-math, SELECT_CC lowering in AArch64
transforms floating point comparisons of the form "a == 0.0 ? 0.0 : x" to
"a == 0.0 ? a : x". But it incorrectly assumes that 'x' and 'a' have
the same type which can lead to a wrong CSEL node that crashes later
due to nonsensical copies.

Differential Revision: https://reviews.llvm.org/D26394


Added:
    llvm/trunk/test/CodeGen/AArch64/csel-zero-float.ll
Modified:
    llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp

Modified: llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp?rev=286231&r1=286230&r2=286231&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp Tue Nov  8 07:34:41 2016
@@ -4106,10 +4106,11 @@ SDValue AArch64TargetLowering::LowerSELE
       ConstantFPSDNode *CTVal = dyn_cast<ConstantFPSDNode>(TVal);
 
       if ((CC == ISD::SETEQ || CC == ISD::SETOEQ || CC == ISD::SETUEQ) &&
-          CTVal && CTVal->isZero())
+          CTVal && CTVal->isZero() && TVal.getValueType() == LHS.getValueType())
         TVal = LHS;
       else if ((CC == ISD::SETNE || CC == ISD::SETONE || CC == ISD::SETUNE) &&
-               CFVal && CFVal->isZero())
+               CFVal && CFVal->isZero() &&
+               FVal.getValueType() == LHS.getValueType())
         FVal = LHS;
     }
   }

Added: llvm/trunk/test/CodeGen/AArch64/csel-zero-float.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/csel-zero-float.ll?rev=286231&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/AArch64/csel-zero-float.ll (added)
+++ llvm/trunk/test/CodeGen/AArch64/csel-zero-float.ll Tue Nov  8 07:34:41 2016
@@ -0,0 +1,15 @@
+; RUN: llc -mtriple=aarch64-none-linux-gnu -enable-unsafe-fp-math < %s
+; There is no invocation to FileCheck as this
+; caused a crash in "Post-RA pseudo instruction expansion"
+
+define double @foo(float *%user, float %t17) {
+  %t16 = load float, float* %user, align 8
+  %conv = fpext float %t16 to double
+  %cmp26 = fcmp fast oeq float %t17, 0.000000e+00
+  %div = fdiv fast float %t16, %t17
+  %div.op = fmul fast float %div, 1.000000e+02
+  %t18 = fpext float %div.op to double
+  %conv31 = select i1 %cmp26, double 0.000000e+00, double %t18
+  ret double %conv31
+}
+