From fd8b1fd7f6cef30bfe102b1d940868c2744f4477 Mon Sep 17 00:00:00 2001 From: Christopher Lamb Date: Tue, 18 Dec 2007 20:30:28 +0000 Subject: [PATCH] Remove an orthogonal transformation of the selection condition from my most recent submission. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45169 91177308-0d34-0410-b5e6-96231b3b80d8 --- .../Scalar/InstructionCombining.cpp | 32 ++----------------- .../InstCombine/2007-12-18-AddSelCmpSub.ll | 11 +------ 2 files changed, 3 insertions(+), 40 deletions(-) diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index d64afbbda1f..dec298b14b1 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -2131,9 +2131,6 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) { } } - // add (select (icmp 0 (sub m A)) X Y) A -> - // add (select (icmp A m) X Y) A - // // add (select X 0 (sub n A)) A -> // select X A n { @@ -2147,27 +2144,6 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) { Value *TV = SI->getTrueValue(); Value *FV = SI->getFalseValue(); Value *A; - - // Can we fold the add into the argument of the compare? - Value *Cond = SI->getCondition(); - if (ICmpInst *IC = dyn_cast(Cond)) { - Value *ICOp0 = IC->getOperand(0); - Value *ICOp1 = IC->getOperand(1); - ConstantInt *C3, *C4; - - // Check both arguments of the compare for a matching subtract. - if (match(ICOp0, m_ConstantInt(C3)) && C3->getValue() == 0 && - match(ICOp1, m_Sub(m_ConstantInt(C4), m_Value(A))) && - A == Other) { - // We managed to fold the add into the RHS of the select condition. - Cond = new ICmpInst(IC->getPredicate(), A, C4, "asis", SI); - } else if (match(ICOp1, m_ConstantInt(C3)) && C3->getValue() == 0 && - match(ICOp0, m_Sub(m_ConstantInt(C4), m_Value(A))) && - A == Other) { - // We managed to fold the add into the LHS of the select condition. - Cond = new ICmpInst(IC->getPredicate(), C4, A, "asis", SI); - } - } // Can we fold the add into the argument of the select? // We check both true and false select arguments for a matching subtract. @@ -2177,17 +2153,13 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) { A == Other) { // We managed to fold the add into the true select value, // picking up a simplified condition, if available. - return new SelectInst(Cond, C2, A, "adselsub"); + return new SelectInst(SI->getCondition(), C2, A); } else if (match(TV, m_ConstantInt(C1)) && C1->getValue() == 0 && match(FV, m_Sub(m_ConstantInt(C2), m_Value(A))) && A == Other) { // We managed to fold the add into the false select value, // picking up a simplified condition, if available. - return new SelectInst(Cond, A, C2, "adselsub"); - } else if (Cond != SI->getCondition()) { - // We only managed to fold the add into the select condition. - SI->setOperand(0, Cond); - Changed = true; + return new SelectInst(SI->getCondition(), A, C2); } } } diff --git a/test/Transforms/InstCombine/2007-12-18-AddSelCmpSub.ll b/test/Transforms/InstCombine/2007-12-18-AddSelCmpSub.ll index 94d6c968920..e44fc6f099a 100644 --- a/test/Transforms/InstCombine/2007-12-18-AddSelCmpSub.ll +++ b/test/Transforms/InstCombine/2007-12-18-AddSelCmpSub.ll @@ -1,4 +1,4 @@ -; RUN: llvm-as < %s | opt -instcombine | llvm-dis | not grep {sub} +; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {add} | count 1 define i32 @foo(i32 %a) { entry: @@ -19,15 +19,6 @@ entry: ret i32 %tmp12 } -define i32 @baz(i32 %a) { -entry: - %tmp15 = sub i32 99, %a ; [#uses=1] - %tmp16 = icmp slt i32 %tmp15, 0 ; [#uses=1] - %smax = select i1 %tmp16, i32 0, i32 42 ; [#uses=1] - %tmp12 = add i32 %smax, %a ; [#uses=1] - ret i32 %tmp12 -} - define i32 @fun(i32 %a) { entry: %tmp15 = sub i32 99, %a ; [#uses=1] -- 2.34.1