From 70c0d4f7eb9c14bccc8a585be4086712e46bfbdb Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Sat, 3 Apr 2010 06:16:22 +0000 Subject: [PATCH] improve comment and drop a dead check. If PH had no uses, it would have been deleted by RecursivelyDeleteTriviallyDeadInstructions git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100275 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Scalar/IndVarSimplify.cpp | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/lib/Transforms/Scalar/IndVarSimplify.cpp b/lib/Transforms/Scalar/IndVarSimplify.cpp index b5fdd0c4a17..650231b8e5c 100644 --- a/lib/Transforms/Scalar/IndVarSimplify.cpp +++ b/lib/Transforms/Scalar/IndVarSimplify.cpp @@ -759,10 +759,14 @@ void IndVarSimplify::HandleFloatingPointIV(Loop *L, PHINode *PH) { Incr->replaceAllUsesWith(UndefValue::get(Incr->getType())); RecursivelyDeleteTriviallyDeadInstructions(Incr); - // Replace floating induction variable, if it isn't already deleted. - // Give SIToFPInst preference over UIToFPInst because it is faster on - // platforms that are widely used. - if (WeakPH && !PH->use_empty()) { + // If the FP induction variable still has uses, this is because something else + // in the loop uses its value. In order to canonicalize the induction + // variable, we chose to eliminate the IV and rewrite it in terms of an + // int->fp cast. + // + // We give preference to sitofp over uitofp because it is faster on most + // platforms. + if (WeakPH) { if (CanUseSIToFP(InitValueVal, ExitValueVal, InitValue, ExitValue)) { SIToFPInst *Conv = new SIToFPInst(NewPHI, PH->getType(), "indvar.conv", PH->getParent()->getFirstNonPHI()); -- 2.34.1