[llvm] r191668 - Fix a bug in InstCombine where it attempted to cast a Value* to an Instruction*

[Joey Gouly]

Author: joey
Date: Mon Sep 30 09:18:35 2013
New Revision: 191668

URL: http://llvm.org/viewvc/llvm-project?rev=191668&view=rev
Log:
Fix a bug in InstCombine where it attempted to cast a Value* to an Instruction*
when it was actually a Constant*.

There are quite a few other casts to Instruction that might have the same problem,
but this is the only one I have a test case for.

Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
    llvm/trunk/test/Transforms/InstCombine/fmul.ll

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp?rev=191668&r1=191667&r2=191668&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp Mon Sep 30 09:18:35 2013
@@ -519,10 +519,10 @@ Instruction *InstCombiner::visitFMul(Bin
       if (Opnd0->hasOneUse()) {
         // -X * Y => -(X*Y) (Promote negation as high as possible)
         Value *T = Builder->CreateFMul(N0, Opnd1);
-        cast<Instruction>(T)->setDebugLoc(I.getDebugLoc());
         Instruction *Neg = BinaryOperator::CreateFNeg(T);
         if (I.getFastMathFlags().any()) {
-          cast<Instruction>(T)->copyFastMathFlags(&I);
+          if (Instruction *TI = dyn_cast<Instruction>(T))
+            TI->copyFastMathFlags(&I);
           Neg->copyFastMathFlags(&I);
         }
         return Neg;

Modified: llvm/trunk/test/Transforms/InstCombine/fmul.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/fmul.ll?rev=191668&r1=191667&r2=191668&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/fmul.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/fmul.ll Mon Sep 30 09:18:35 2013
@@ -70,3 +70,26 @@ define float @test7(float %x, float %y)
 ; CHECK-LABEL: @test7(
 ; CHECK: fsub float -0.000000e+00, %x
 }
+
+; Don't crash when attempting to cast a constant FMul to an instruction.
+define void @test8(i32* %inout) {
+entry:
+  %0 = load i32* %inout, align 4
+  %conv = uitofp i32 %0 to float
+  %vecinit = insertelement <4 x float> <float 0.000000e+00, float 0.000000e+00, float 0.000000e+00, float undef>, float %conv, i32 3
+  %sub = fsub <4 x float> <float -0.000000e+00, float -0.000000e+00, float -0.000000e+00, float -0.000000e+00>, %vecinit
+  %1 = shufflevector <4 x float> %sub, <4 x float> undef, <4 x i32> <i32 1, i32 1, i32 1, i32 1>
+  %mul = fmul <4 x float> zeroinitializer, %1
+  br label %for.cond
+
+for.cond:                                         ; preds = %for.body, %entry
+  %local_var_7.0 = phi <4 x float> [ %mul, %entry ], [ %2, %for.body ]
+  br i1 undef, label %for.body, label %for.end
+
+for.body:                                         ; preds = %for.cond
+  %2 = insertelement <4 x float> %local_var_7.0, float 0.000000e+00, i32 2
+  br label %for.cond
+
+for.end:                                          ; preds = %for.cond
+  ret void
+}