[LoopUnrollAnalyzer] Fix a crash in UnrolledInstAnalyzer::visitCastInst.

This fixes PR27847.

llvm-svn: 270517

2 files changed, 26 insertions, 2 deletions

diff --git a/llvm/lib/Analysis/LoopUnrollAnalyzer.cpp b/llvm/lib/Analysis/LoopUnrollAnalyzer.cpp
index a044e6bd330..413cf343c97 100644
--- a/llvm/lib/Analysis/LoopUnrollAnalyzer.cpp
+++ b/llvm/lib/Analysis/LoopUnrollAnalyzer.cpp
@@ -141,12 +141,17 @@ bool UnrolledInstAnalyzer::visitCastInst(CastInst &I) {
   Constant *COp = dyn_cast<Constant>(I.getOperand(0));
   if (!COp)
     COp = SimplifiedValues.lookup(I.getOperand(0));
-  if (COp)
+  if (COp) {
+    if (COp->getType() == I.getType()) {
+      SimplifiedValues[&I] = cast<Constant>(COp);
+      return true;
+    }
     if (Constant *C =
             ConstantExpr::getCast(I.getOpcode(), COp, I.getType())) {
       SimplifiedValues[&I] = C;
       return true;
     }
+  }
 
   return Base::visitCastInst(I);
 }
diff --git a/llvm/test/Transforms/LoopUnroll/full-unroll-crashers.ll b/llvm/test/Transforms/LoopUnroll/full-unroll-crashers.ll
index e932851042a..991cb309bf4 100644
--- a/llvm/test/Transforms/LoopUnroll/full-unroll-crashers.ll
+++ b/llvm/test/Transforms/LoopUnroll/full-unroll-crashers.ll
@@ -1,5 +1,5 @@
 ; Check that we don't crash on corner cases.
-; RUN: opt < %s -S -loop-unroll -unroll-max-iteration-count-to-analyze=1000 -unroll-threshold=10 -unroll-percent-dynamic-cost-saved-threshold=20 -o /dev/null
+; RUN: opt < %s -S -loop-unroll -unroll-max-iteration-count-to-analyze=1000 -unroll-threshold=1 -unroll-percent-dynamic-cost-saved-threshold=20 -o /dev/null
 target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
 
 @known_constant = internal unnamed_addr constant [10 x i32] [i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1], align 16
@@ -100,3 +100,22 @@ for.body:
 for.exit:
   ret <4 x i32> %r
 }
+
+define void @ptrtoint_cast() optsize {
+entry:
+  br label %for.body
+
+for.body:
+  br i1 true, label %for.inc, label %if.then
+
+if.then:
+  %arraydecay = getelementptr inbounds [1 x i32], [1 x i32]* null, i64 0, i64 0
+  %x = ptrtoint i32* %arraydecay to i64
+  br label %for.inc
+
+for.inc:
+  br i1 false, label %for.body, label %for.cond.cleanup
+
+for.cond.cleanup:
+  ret void
+}