From: Dan Gohman <gohman@apple.com>
Date: Thu, 1 Jul 2010 03:49:59 +0000 (+0000)
Subject: Fast isel no longer needs DeadMachineInstrElim to clean up after it.
X-Git-Tag: android-x86-6.0-r1~1003^2~5159
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=a528bc0e8af8e4d70ba03e03319cce7c5775e4ea;p=android-x86%2Fexternal-llvm.git

Fast isel no longer needs DeadMachineInstrElim to clean up after it.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107381 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/LLVMTargetMachine.cpp b/lib/CodeGen/LLVMTargetMachine.cpp
index d437370031d..bf3137e4953 100644
--- a/lib/CodeGen/LLVMTargetMachine.cpp
+++ b/lib/CodeGen/LLVMTargetMachine.cpp
@@ -329,19 +329,15 @@ bool LLVMTargetMachine::addCommonCodeGenPasses(PassManagerBase &PM,
   if (OptLevel != CodeGenOpt::None)
     PM.add(createOptimizePHIsPass());
 
-  // Delete dead machine instructions regardless of optimization level.
-  //
-  // At -O0, fast-isel frequently creates dead instructions.
-  //
-  // With optimization, dead code should already be eliminated. However
-  // there is one known exception: lowered code for arguments that are only
-  // used by tail calls, where the tail calls reuse the incoming stack
-  // arguments directly (see t11 in test/CodeGen/X86/sibcall.ll).
-  PM.add(createDeadMachineInstructionElimPass());
-  printAndVerify(PM, "After codegen DCE pass",
-                 /* allowDoubleDefs= */ true);
-
   if (OptLevel != CodeGenOpt::None) {
+    // With optimization, dead code should already be eliminated. However
+    // there is one known exception: lowered code for arguments that are only
+    // used by tail calls, where the tail calls reuse the incoming stack
+    // arguments directly (see t11 in test/CodeGen/X86/sibcall.ll).
+    PM.add(createDeadMachineInstructionElimPass());
+    printAndVerify(PM, "After codegen DCE pass",
+                   /* allowDoubleDefs= */ true);
+
     PM.add(createOptimizeExtsPass());
     if (!DisableMachineLICM)
       PM.add(createMachineLICMPass());