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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191668 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index 9c310f04dcdd0e1f191fc1a8798362ae9e0b7d85..5c5ee1256f3939d702800036f6bfa89dc48b12f3 100644 (file)
--- a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -519,10 +519,10 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
       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;

diff --git a/test/Transforms/InstCombine/fmul.ll b/test/Transforms/InstCombine/fmul.ll
index cf57bed82a0f4f25b3cc80aa339b31f8845eda80..402ee52e624af2c0f31d8bce41d5a0c2dd7b4e15 100644 (file)
--- a/test/Transforms/InstCombine/fmul.ll
+++ b/test/Transforms/InstCombine/fmul.ll
@@ -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
+}