The early if conversion pass is ready to be used as an opt-in.

Enable the pass by default for targets that request it, and change the
-enable-early-ifcvt to the opposite -disable-early-ifcvt.

There are still some x86 regressions when enabling early if-conversion
because of the missing machine models. Disable the pass for x86 until
machine models are added.

llvm-svn: 165075

3 files changed, 11 insertions, 5 deletions

diff --git a/llvm/lib/CodeGen/Passes.cpp b/llvm/lib/CodeGen/Passes.cpp
index a6dd5decbea..4ea21d4ff7b 100644
--- a/llvm/lib/CodeGen/Passes.cpp
+++ b/llvm/lib/CodeGen/Passes.cpp
@@ -49,8 +49,8 @@ static cl::opt<bool> DisableSSC("disable-ssc", cl::Hidden,
     cl::desc("Disable Stack Slot Coloring"));
 static cl::opt<bool> DisableMachineDCE("disable-machine-dce", cl::Hidden,
     cl::desc("Disable Machine Dead Code Elimination"));
-static cl::opt<bool> EnableEarlyIfConversion("enable-early-ifcvt", cl::Hidden,
-    cl::desc("Enable Early If-conversion"));
+static cl::opt<bool> DisableEarlyIfConversion("disable-early-ifcvt", cl::Hidden,
+    cl::desc("Disable Early If-conversion"));
 static cl::opt<bool> DisableMachineLICM("disable-machine-licm", cl::Hidden,
     cl::desc("Disable Machine LICM"));
 static cl::opt<bool> DisableMachineCSE("disable-machine-cse", cl::Hidden,
@@ -161,7 +161,7 @@ static AnalysisID overridePass(AnalysisID StandardID, AnalysisID TargetID) {
     return applyDisable(TargetID, DisableMachineDCE);
 
   if (StandardID == &EarlyIfConverterID)
-    return applyDisable(TargetID, !EnableEarlyIfConversion);
+    return applyDisable(TargetID, DisableEarlyIfConversion);
 
   if (StandardID == &MachineLICMID)
     return applyDisable(TargetID, DisableMachineLICM);
diff --git a/llvm/lib/Target/X86/X86TargetMachine.cpp b/llvm/lib/Target/X86/X86TargetMachine.cpp
index b7ba568394b..b05b31b14ab 100644
--- a/llvm/lib/Target/X86/X86TargetMachine.cpp
+++ b/llvm/lib/Target/X86/X86TargetMachine.cpp
@@ -113,6 +113,12 @@ UseVZeroUpper("x86-use-vzeroupper",
   cl::desc("Minimize AVX to SSE transition penalty"),
   cl::init(true));
 
+// Temporary option to control early if-conversion for x86 while adding machine
+// models.
+static cl::opt<bool>
+X86EarlyIfConv("x86-early-ifcvt",
+	       cl::desc("Enable early if-conversion on X86"));
+
 //===----------------------------------------------------------------------===//
 // Pass Pipeline Configuration
 //===----------------------------------------------------------------------===//
@@ -142,7 +148,7 @@ public:
 TargetPassConfig *X86TargetMachine::createPassConfig(PassManagerBase &PM) {
   X86PassConfig *PC = new X86PassConfig(this, PM);
 
-  if (Subtarget.hasCMov())
+  if (X86EarlyIfConv && Subtarget.hasCMov())
     PC->enablePass(&EarlyIfConverterID);
 
   return PC;
diff --git a/llvm/test/CodeGen/X86/early-ifcvt.ll b/llvm/test/CodeGen/X86/early-ifcvt.ll
index 7883ffabd56..17b3cb22cd4 100644
--- a/llvm/test/CodeGen/X86/early-ifcvt.ll
+++ b/llvm/test/CodeGen/X86/early-ifcvt.ll
@@ -1,4 +1,4 @@
-; RUN: llc < %s -enable-early-ifcvt -stress-early-ifcvt | FileCheck %s
+; RUN: llc < %s -x86-early-ifcvt -stress-early-ifcvt | FileCheck %s
 target triple = "x86_64-apple-macosx10.8.0"
 
 ; CHECK: mm2