[MergeICmps] Re-commit rL324317 "Enable the MergeICmps Pass by default."

With fixes from rL324341.

Original commit message:

[MergeICmps] Enable the MergeICmps Pass by default.

Summary: Now that PR33325 is fixed, this should always improve the generated code.

Reviewers: spatel

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D42793

llvm-svn: 324465

1 files changed, 4 insertions, 5 deletions

diff --git a/llvm/lib/CodeGen/TargetPassConfig.cpp b/llvm/lib/CodeGen/TargetPassConfig.cpp
index 43fec69495b..84597570c16 100644
--- a/llvm/lib/CodeGen/TargetPassConfig.cpp
+++ b/llvm/lib/CodeGen/TargetPassConfig.cpp
@@ -94,10 +94,9 @@ static cl::opt<bool> EnableImplicitNullChecks(
     "enable-implicit-null-checks",
     cl::desc("Fold null checks into faulting memory operations"),
     cl::init(false), cl::Hidden);
-static cl::opt<bool>
-    EnableMergeICmps("enable-mergeicmps",
-                     cl::desc("Merge ICmp chains into a single memcmp"),
-                     cl::init(false), cl::Hidden);
+static cl::opt<bool> DisableMergeICmps("disable-mergeicmps",
+    cl::desc("Disable MergeICmps Pass"),
+    cl::init(false), cl::Hidden);
 static cl::opt<bool> PrintLSR("print-lsr-output", cl::Hidden,
     cl::desc("Print LLVM IR produced by the loop-reduce pass"));
 static cl::opt<bool> PrintISelInput("print-isel-input", cl::Hidden,
@@ -596,7 +595,7 @@ void TargetPassConfig::addIRPasses() {
     // loads and compares. ExpandMemCmpPass then tries to expand those calls
     // into optimally-sized loads and compares. The transforms are enabled by a
     // target lowering hook.
-    if (EnableMergeICmps)
+    if (!DisableMergeICmps)
       addPass(createMergeICmpsPass());
     addPass(createExpandMemCmpPass());
   }