[AArch64][GlobalISel] Inline tiny memcpy et al at -O0.
FastISel already does this since the initial arm64 port was upstreamed, so
it seems there are no issues with doing this at -O0 for very small memcpys.
Gives a 0.2% geomean code size improvement on CTMark.
Differential Revision: https://reviews.llvm.org/D65758
llvm-svn: 367919
diff --git a/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
index 373d52f..9149813 100644
--- a/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
@@ -861,7 +861,7 @@
return true;
}
-bool CombinerHelper::tryCombineMemCpyFamily(MachineInstr &MI) {
+bool CombinerHelper::tryCombineMemCpyFamily(MachineInstr &MI, unsigned MaxLen) {
// This combine is fairly complex so it's not written with a separate
// matcher function.
assert(MI.getOpcode() == TargetOpcode::G_INTRINSIC_W_SIDE_EFFECTS);
@@ -900,6 +900,9 @@
return true;
}
+ if (MaxLen && KnownLen > MaxLen)
+ return false;
+
if (ID == Intrinsic::memcpy)
return optimizeMemcpy(MI, Dst, Src, KnownLen, DstAlign, SrcAlign, IsVolatile);
if (ID == Intrinsic::memmove)
diff --git a/llvm/lib/Target/AArch64/AArch64PreLegalizerCombiner.cpp b/llvm/lib/Target/AArch64/AArch64PreLegalizerCombiner.cpp
index 5ec209a..835fcf0 100644
--- a/llvm/lib/Target/AArch64/AArch64PreLegalizerCombiner.cpp
+++ b/llvm/lib/Target/AArch64/AArch64PreLegalizerCombiner.cpp
@@ -56,9 +56,12 @@
case Intrinsic::memcpy:
case Intrinsic::memmove:
case Intrinsic::memset: {
+ // If we're at -O0 set a maxlen of 32 to inline, otherwise let the other
+ // heuristics decide.
+ unsigned MaxLen = EnableOpt ? 0 : 32;
// Try to inline memcpy type calls if optimizations are enabled.
- return (EnableOpt && !EnableOptSize) ? Helper.tryCombineMemCpyFamily(MI)
- : false;
+ return (!EnableOptSize) ? Helper.tryCombineMemCpyFamily(MI, MaxLen)
+ : false;
}
default:
break;