[llvm-commits] [llvm] r69836 - in /llvm/trunk: lib/Transforms/Scalar/IndVarSimplify.cpp test/Transforms/IndVarSimplify/2009-04-22-IndvarCrash.ll

[Evan Cheng]

Author: evancheng
Date: Wed Apr 22 17:45:37 2009
New Revision: 69836

URL: http://llvm.org/viewvc/llvm-project?rev=69836&view=rev
Log:
Avoid deferencing use_begin() if value does not have a use.

Added:
    llvm/trunk/test/Transforms/IndVarSimplify/2009-04-22-IndvarCrash.ll
Modified:
    llvm/trunk/lib/Transforms/Scalar/IndVarSimplify.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/IndVarSimplify.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/IndVarSimplify.cpp?rev=69836&r1=69835&r2=69836&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/IndVarSimplify.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/IndVarSimplify.cpp Wed Apr 22 17:45:37 2009
@@ -806,6 +806,7 @@
         // (RHS doesn't have to be constant.  There should be a better approach
         // than bottom-up pattern matching for this...)
         if (UInst && UInst->getOpcode()==Instruction::And &&
+            !UInst->use_empty() &&
             allUsesAreSameTyped(Instruction::ZExt, UInst) &&
             isa<ConstantInt>(UInst->getOperand(1))) {
           uint64_t newBitSize = LargestType->getPrimitiveSizeInBits();

Added: llvm/trunk/test/Transforms/IndVarSimplify/2009-04-22-IndvarCrash.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/IndVarSimplify/2009-04-22-IndvarCrash.ll?rev=69836&view=auto

==============================================================================
--- llvm/trunk/test/Transforms/IndVarSimplify/2009-04-22-IndvarCrash.ll (added)
+++ llvm/trunk/test/Transforms/IndVarSimplify/2009-04-22-IndvarCrash.ll Wed Apr 22 17:45:37 2009
@@ -0,0 +1,17 @@
+; RUN: llvm-as < %s | opt -indvars
+
+define i32 @t() nounwind ssp {
+entry:
+	br label %bb32
+
+bb32:		; preds = %bb32, %entry
+	%mbPartIdx.0.reg2mem.0 = phi i8 [ %2, %bb32 ], [ 0, %entry ]		; <i8> [#uses=3]
+	%0 = and i8 %mbPartIdx.0.reg2mem.0, 1		; <i8> [#uses=0]
+	%1 = zext i8 %mbPartIdx.0.reg2mem.0 to i64		; <i64> [#uses=0]
+	%2 = add i8 %mbPartIdx.0.reg2mem.0, 1		; <i8> [#uses=2]
+	%3 = icmp ugt i8 %2, 3		; <i1> [#uses=1]
+	br i1 %3, label %bb41, label %bb32
+
+bb41:		; preds = %bb32
+	ret i32 0
+}