[X86] Reduce memory allocations in X86TargetMachine::getSubtargetImpl
We performed a number of memory allocations each time getTTI was called,
remove them by using SmallString.
No functionality change intended.
llvm-svn: 270246
diff --git a/llvm/lib/Target/X86/X86TargetMachine.cpp b/llvm/lib/Target/X86/X86TargetMachine.cpp
index 3ff847a..31918d0 100644
--- a/llvm/lib/Target/X86/X86TargetMachine.cpp
+++ b/llvm/lib/Target/X86/X86TargetMachine.cpp
@@ -182,12 +182,12 @@
Attribute CPUAttr = F.getFnAttribute("target-cpu");
Attribute FSAttr = F.getFnAttribute("target-features");
- std::string CPU = !CPUAttr.hasAttribute(Attribute::None)
- ? CPUAttr.getValueAsString().str()
- : TargetCPU;
- std::string FS = !FSAttr.hasAttribute(Attribute::None)
- ? FSAttr.getValueAsString().str()
- : TargetFS;
+ SmallString<32> CPU = !CPUAttr.hasAttribute(Attribute::None)
+ ? CPUAttr.getValueAsString()
+ : (StringRef)TargetCPU;
+ SmallString<512> FS = !FSAttr.hasAttribute(Attribute::None)
+ ? FSAttr.getValueAsString()
+ : (StringRef)TargetFS;
// FIXME: This is related to the code below to reset the target options,
// we need to know whether or not the soft float flag is set on the
@@ -201,7 +201,12 @@
if (SoftFloat)
FS += FS.empty() ? "+soft-float" : ",+soft-float";
- auto &I = SubtargetMap[CPU + FS];
+ SmallString<544> Key;
+ Key.reserve(CPU.size() + FS.size());
+ Key += CPU;
+ Key += FS;
+
+ auto &I = SubtargetMap[Key];
if (!I) {
// This needs to be done before we create a new subtarget since any
// creation will depend on the TM and the code generation flags on the