[PATCH] D26394: [AArch64] Fix incorrect CSEL node created

[Roger Ferrer Ibanez via llvm-commits]

rogfer01 created this revision.
rogfer01 added reviewers: jmolloy, t.p.northover, evandro.
rogfer01 added a subscriber: llvm-commits.
Herald added subscribers: rengolin, aemerson.

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 fails later
due to nonsensical copies.

This issue was introduced in https://reviews.llvm.org/rL284531


https://reviews.llvm.org/D26394

Files:
  lib/Target/AArch64/AArch64ISelLowering.cpp
  test/CodeGen/AArch64/csel-zero-float.ll


Index: test/CodeGen/AArch64/csel-zero-float.ll
===================================================================
--- /dev/null
+++ test/CodeGen/AArch64/csel-zero-float.ll
@@ -0,0 +1,13 @@
+; RUN: llc -mtriple=aarch64-none-linux-gnu -enable-unsafe-fp-math < %s
+
+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
+}
+
Index: lib/Target/AArch64/AArch64ISelLowering.cpp
===================================================================
--- lib/Target/AArch64/AArch64ISelLowering.cpp
+++ lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -4106,10 +4106,11 @@
       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;
     }
   }


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D26394.77173.patch
Type: text/x-patch
Size: 1439 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20161108/19820b32/attachment.bin>