[llvm] r245741 - [PowerPC] PPCVSXFMAMutate should not segfault on undef input registers

[Hal Finkel via llvm-commits]

Author: hfinkel
Date: Fri Aug 21 16:34:24 2015
New Revision: 245741

URL: http://llvm.org/viewvc/llvm-project?rev=245741&view=rev
Log:
[PowerPC] PPCVSXFMAMutate should not segfault on undef input registers

When PPCVSXFMAMutate would look at the input addend register, it would get its
input value number. This would fail, however, if the register was undef,
causing a segfault. Don't segfault (just skip such FMA instructions).

Fixes the test case from PR24542 (although that may have been over-reduced).

Added:
    llvm/trunk/test/CodeGen/PowerPC/vsx-fma-mutate-undef.ll
Modified:
    llvm/trunk/lib/Target/PowerPC/PPCVSXFMAMutate.cpp

Modified: llvm/trunk/lib/Target/PowerPC/PPCVSXFMAMutate.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/PPCVSXFMAMutate.cpp?rev=245741&r1=245740&r2=245741&view=diff
==============================================================================
--- llvm/trunk/lib/Target/PowerPC/PPCVSXFMAMutate.cpp (original)
+++ llvm/trunk/lib/Target/PowerPC/PPCVSXFMAMutate.cpp Fri Aug 21 16:34:24 2015
@@ -103,6 +103,11 @@ protected:
 
         VNInfo *AddendValNo =
           LIS->getInterval(MI->getOperand(1).getReg()).Query(FMAIdx).valueIn();
+        if (!AddendValNo) {
+          // This can be null if the register is undef.
+          continue;
+        }
+
         MachineInstr *AddendMI = LIS->getInstructionFromIndex(AddendValNo->def);
 
         // The addend and this instruction must be in the same block.

Added: llvm/trunk/test/CodeGen/PowerPC/vsx-fma-mutate-undef.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/PowerPC/vsx-fma-mutate-undef.ll?rev=245741&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/PowerPC/vsx-fma-mutate-undef.ll (added)
+++ llvm/trunk/test/CodeGen/PowerPC/vsx-fma-mutate-undef.ll Fri Aug 21 16:34:24 2015
@@ -0,0 +1,33 @@
+; RUN: llc < %s | FileCheck %s
+target datalayout = "e-m:e-i64:64-n32:64"
+target triple = "powerpc64le-unknown-linux-gnu"
+
+; Function Attrs: nounwind
+define void @acosh_float8() #0 {
+entry:
+  br i1 undef, label %if.then, label %if.end
+
+if.then:                                          ; preds = %entry
+  %0 = tail call <4 x float> @llvm.fmuladd.v4f32(<4 x float> undef, <4 x float> <float 0x3FE62E4200000000, float 0x3FE62E4200000000, float 0x3FE62E4200000000, float 0x3FE62E4200000000>, <4 x float> undef) #0
+  %astype.i.i.74.i = bitcast <4 x float> %0 to <4 x i32>
+  %and.i.i.76.i = and <4 x i32> %astype.i.i.74.i, undef
+  %or.i.i.79.i = or <4 x i32> %and.i.i.76.i, undef
+  %astype5.i.i.80.i = bitcast <4 x i32> %or.i.i.79.i to <4 x float>
+  %1 = shufflevector <4 x float> %astype5.i.i.80.i, <4 x float> undef, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 undef, i32 undef, i32 undef, i32 undef>
+  %2 = shufflevector <8 x float> undef, <8 x float> %1, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 8, i32 9, i32 10, i32 11>
+  store <8 x float> %2, <8 x float>* undef, align 32
+  br label %if.end
+
+; CHECK-LABEL: @acosh_float8
+; CHECK: xvmaddasp
+
+if.end:                                           ; preds = %if.then, %entry
+  ret void
+}
+
+; Function Attrs: nounwind readnone
+declare <4 x float> @llvm.fmuladd.v4f32(<4 x float>, <4 x float>, <4 x float>) #1
+
+attributes #0 = { nounwind }
+attributes #1 = { nounwind readnone }
+