From 4f3052403ca5ea9542a118c2e54ff9c82038f41c Mon Sep 17 00:00:00 2001 From: Andrew Trick Date: Thu, 17 Nov 2011 23:36:35 +0000 Subject: Fix an overly general check in SimplifyIndvar to handle useless phi cycles. The right way to check for a binary operation is cast. The original check: cast && numOperands() == 2 would match phi "instructions", leading to an infinite loop in extreme corner case: a useless phi with operands [self, constant] that prior optimization passes failed to remove, being used in the loop by another useless phi, in turn being used by an lshr or udiv. Fixes PR11350: runaway iteration assertion. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144935 91177308-0d34-0410-b5e6-96231b3b80d8 --- .../IndVarSimplify/2011-11-17-selfphi.ll | 29 ++++++++++++++++++++++ 1 file changed, 29 insertions(+) create mode 100644 test/Transforms/IndVarSimplify/2011-11-17-selfphi.ll (limited to 'test/Transforms') diff --git a/test/Transforms/IndVarSimplify/2011-11-17-selfphi.ll b/test/Transforms/IndVarSimplify/2011-11-17-selfphi.ll new file mode 100644 index 0000000..ccf2595 --- /dev/null +++ b/test/Transforms/IndVarSimplify/2011-11-17-selfphi.ll @@ -0,0 +1,29 @@ +; RUN: opt < %s -indvars -S | FileCheck %s +; PR11350: Check that SimplifyIndvar handles a cycle of useless self-phis. + +; CHECK: @test +; CHECK-NOT: lcssa = phi +define void @test() nounwind { +entry: + br label %for.cond.preheader + +for.cond.preheader: ; preds = %entry + br label %for.cond.outer + +for.cond.outer: ; preds = %for.cond.preheader, %for.end + %p_41.addr.0.ph = phi i32 [ %p_41.addr.1.lcssa, %for.end ], [ 1, %for.cond.preheader ] + br label %for.cond + +for.cond: + br i1 true, label %for.end, label %for.ph + +for.ph: ; preds = %for.cond4.preheader + br label %for.end + +for.end: + %p_41.addr.1.lcssa = phi i32 [ undef, %for.ph ], [ %p_41.addr.0.ph, %for.cond ] + %p_68.lobit.i = lshr i32 %p_41.addr.1.lcssa, 31 + %cmp7 = icmp eq i32 %p_41.addr.1.lcssa, 0 + %conv8 = zext i1 %cmp7 to i32 + br label %for.cond.outer +} -- cgit v1.1