From 8a70192b510e2a0f05493b9212e998017f3d178d Mon Sep 17 00:00:00 2001 From: Peter Collingbourne Date: Fri, 29 Apr 2011 18:47:25 +0000 Subject: [PATCH] SimplifyCFG: Add Trunc, ZExt and SExt to the list of cheap instructions for phi node folding git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130526 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Utils/SimplifyCFG.cpp | 3 +++ test/Transforms/SimplifyCFG/PhiEliminate2.ll | 15 +++++++++------ 2 files changed, 12 insertions(+), 6 deletions(-) diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp index 5177d339597..1bddecb8c40 100644 --- a/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/lib/Transforms/Utils/SimplifyCFG.cpp @@ -261,6 +261,9 @@ static bool DominatesMergePoint(Value *V, BasicBlock *BB, case Instruction::LShr: case Instruction::AShr: case Instruction::ICmp: + case Instruction::Trunc: + case Instruction::ZExt: + case Instruction::SExt: break; // These are all cheap and non-trapping instructions. } diff --git a/test/Transforms/SimplifyCFG/PhiEliminate2.ll b/test/Transforms/SimplifyCFG/PhiEliminate2.ll index c0f6781293d..0b3893d520d 100644 --- a/test/Transforms/SimplifyCFG/PhiEliminate2.ll +++ b/test/Transforms/SimplifyCFG/PhiEliminate2.ll @@ -1,14 +1,17 @@ ; RUN: opt < %s -simplifycfg -S | not grep br -define i32 @test(i1 %C, i32 %V1, i32 %V2) { +define i32 @test(i1 %C, i32 %V1, i32 %V2, i16 %V3) { entry: - br i1 %C, label %then, label %Cont + br i1 %C, label %then, label %else then: ; preds = %entry - %V3 = or i32 %V2, %V1 ; [#uses=1] + %V4 = or i32 %V2, %V1 ; [#uses=1] br label %Cont -Cont: ; preds = %then, %entry - %V4 = phi i32 [ %V1, %entry ], [ %V3, %then ] ; [#uses=0] - call i32 @test( i1 false, i32 0, i32 0 ) ; :0 [#uses=0] +else: ; preds = %entry + %V5 = sext i16 %V3 to i32 ; [#uses=1] + br label %Cont +Cont: ; preds = %then, %else + %V6 = phi i32 [ %V5, %else ], [ %V4, %then ] ; [#uses=0] + call i32 @test( i1 false, i32 0, i32 0, i16 0 ) ; :0 [#uses=0] ret i32 %V1 } -- 2.34.1