Switch the select to branch transformation on by default.

The primitive conservative heuristic seems to give a slight overall
improvement while not regressing stuff. Make it available to wider
testing. If you notice any speed regressions (or significant code
size regressions) let me know!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156258 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/CodeGenPrepare.cpp b/lib/Transforms/Scalar/CodeGenPrepare.cpp
index 291274d715ef0075cc0927f805ee2ca679d41034..24d64b50c2a50ca55aecb7f61946394eeb62baa7 100644 (file)
--- a/lib/Transforms/Scalar/CodeGenPrepare.cpp
+++ b/lib/Transforms/Scalar/CodeGenPrepare.cpp
@@ -71,8 +71,9 @@ static cl::opt<bool> DisableDeleteDeadBlocks(
   "disable-cgp-delete-dead-blocks", cl::Hidden, cl::init(false),
   cl::desc("Disable deleting dead blocks in CodeGenPrepare"));
 
-static cl::opt<bool> EnableSelectToBranch("enable-cgp-select2branch", cl::Hidden,
-  cl::desc("Enable select to branch conversion."));
+static cl::opt<bool> DisableSelectToBranch(
+  "disable-cgp-select2branch", cl::Hidden, cl::init(false),
+  cl::desc("Disable select to branch conversion."));
 
 namespace {
   class CodeGenPrepare : public FunctionPass {
@@ -1132,7 +1133,7 @@ static bool isFormingBranchFromSelectProfitable(SelectInst *SI) {
 bool CodeGenPrepare::OptimizeSelectInst(SelectInst *SI) {
   // If we have a SelectInst that will likely profit from branch prediction,
   // turn it into a branch.
-  if (!EnableSelectToBranch || OptSize || !TLI->isPredictableSelectExpensive())
+  if (DisableSelectToBranch || OptSize || !TLI->isPredictableSelectExpensive())
     return false;
 
   if (!SI->getCondition()->getType()->isIntegerTy(1) ||

diff --git a/test/CodeGen/X86/cmov-into-branch.ll b/test/CodeGen/X86/cmov-into-branch.ll
index 3b450edb3c322b43bedfdae32a341e9a3126eb9e..780746ab1ae44f30ae61c8146c1ef229dca5b04e 100644 (file)
--- a/test/CodeGen/X86/cmov-into-branch.ll
+++ b/test/CodeGen/X86/cmov-into-branch.ll
@@ -1,4 +1,4 @@
-; RUN: llc -march=x86-64 -mcpu=core2 -enable-cgp-select2branch < %s | FileCheck %s
+; RUN: llc -march=x86-64 -mcpu=core2 < %s | FileCheck %s
 
 ; cmp with single-use load, should not form cmov.
 define i32 @test1(double %a, double* nocapture %b, i32 %x, i32 %y)  {

diff --git a/test/CodeGen/X86/cmov.ll b/test/CodeGen/X86/cmov.ll
index 2e7ffbfd546d90bbc95924109bad0bf4564b7ffc..43beac0b6ffa9c64e75c5f3a952ec1bbccebda0d 100644 (file)
--- a/test/CodeGen/X86/cmov.ll
+++ b/test/CodeGen/X86/cmov.ll
@@ -1,4 +1,4 @@
-; RUN: llc < %s -mtriple=x86_64-apple-darwin10 | FileCheck %s
+; RUN: llc < %s -mtriple=x86_64-apple-darwin10 -disable-cgp-select2branch | FileCheck %s
 target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"
 
 define i32 @test1(i32 %x, i32 %n, i32 %w, i32* %vp) nounwind readnone {