From ef2ef3e246aa7d0e048af2a1cf39189714b3ba0c Mon Sep 17 00:00:00 2001
From: Pedro Artigas <partigas@apple.com>
Date: Fri, 30 Nov 2012 22:47:15 +0000
Subject: [PATCH] reversed the logic of the log2 detection routine to reduce
the number of nested ifs
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169049 91177308-0d34-0410-b5e6-96231b3b80d8
---
.../InstCombine/InstCombineMulDivRem.cpp | 54 ++++++++++---------
1 file changed, 29 insertions(+), 25 deletions(-)
diff --git a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index b0b9bac8f75..2fc5f85cd7e 100644
--- a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -261,31 +261,35 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) {
//
static void detectLog2OfHalf(Value *&Op, Value *&Y, IntrinsicInst *&Log2) {
- if (Op->hasOneUse()) {
- if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Op)) {
- if (II->getIntrinsicID() == Intrinsic::log2 &&
- II->hasUnsafeAlgebra()) {
- Log2 = II;
- Value *OpLog2Of = II->getArgOperand(0);
- if (OpLog2Of->hasOneUse()) {
- if (Instruction *I = dyn_cast<Instruction>(OpLog2Of)) {
- if (I->getOpcode() == Instruction::FMul &&
- I->hasUnsafeAlgebra()) {
- ConstantFP *CFP = dyn_cast<ConstantFP>(I->getOperand(0));
- if (CFP && CFP->isExactlyValue(0.5)) {
- Y = I->getOperand(1);
- } else {
- CFP = dyn_cast<ConstantFP>(I->getOperand(1));
- if (CFP && CFP->isExactlyValue(0.5)) {
- Y = I->getOperand(0);
- }
- }
- }
- }
- }
- }
- }
- }
+
+ if (!Op->hasOneUse())
+ return;
+
+ IntrinsicInst *II = dyn_cast<IntrinsicInst>(Op);
+ if (!II)
+ return;
+ if (II->getIntrinsicID() != Intrinsic::log2 || !II->hasUnsafeAlgebra())
+ return;
+ Log2 = II;
+
+ Value *OpLog2Of = II->getArgOperand(0);
+ if (!OpLog2Of->hasOneUse())
+ return;
+
+ Instruction *I = dyn_cast<Instruction>(OpLog2Of);
+ if (!I)
+ return;
+ if (I->getOpcode() != Instruction::FMul || !I->hasUnsafeAlgebra())
+ return;
+
+ ConstantFP *CFP = dyn_cast<ConstantFP>(I->getOperand(0));
+ if (CFP && CFP->isExactlyValue(0.5)) {
+ Y = I->getOperand(1);
+ return;
+ }
+ CFP = dyn_cast<ConstantFP>(I->getOperand(1));
+ if (CFP && CFP->isExactlyValue(0.5))
+ Y = I->getOperand(0);
}
Instruction *InstCombiner::visitFMul(BinaryOperator &I) {