Change -prefer-32bit-thumb to attribute -mattr=+32bit instead to disable more 32-bit to 16-bit optimizations.
llvm-svn: 110584
diff --git a/llvm/lib/Target/ARM/ARM.td b/llvm/lib/Target/ARM/ARM.td
index fa64d6c..e76a47d 100644
--- a/llvm/lib/Target/ARM/ARM.td
+++ b/llvm/lib/Target/ARM/ARM.td
@@ -65,6 +65,9 @@
"true",
"Use NEON for single precision FP">;
+// Disable 32-bit to 16-bit narrowing for experimentation.
+def FeaturePref32BitThumb : SubtargetFeature<"32bit", "Pref32BitThumb", "true",
+ "Prefer 32-bit Thumb instrs">;
//===----------------------------------------------------------------------===//
// ARM Processors supported.
diff --git a/llvm/lib/Target/ARM/ARMConstantIslandPass.cpp b/llvm/lib/Target/ARM/ARMConstantIslandPass.cpp
index 118b2de..224842d 100644
--- a/llvm/lib/Target/ARM/ARMConstantIslandPass.cpp
+++ b/llvm/lib/Target/ARM/ARMConstantIslandPass.cpp
@@ -357,7 +357,7 @@
}
// Shrink 32-bit Thumb2 branch, load, and store instructions.
- if (isThumb2)
+ if (isThumb2 && !STI->prefers32BitThumb())
MadeChange |= OptimizeThumb2Instructions(MF);
// After a while, this might be made debug-only, but it is not expensive.
diff --git a/llvm/lib/Target/ARM/ARMSubtarget.h b/llvm/lib/Target/ARM/ARMSubtarget.h
index e7d92ed..3f24558 100644
--- a/llvm/lib/Target/ARM/ARMSubtarget.h
+++ b/llvm/lib/Target/ARM/ARMSubtarget.h
@@ -84,6 +84,10 @@
/// instructions.
bool HasT2ExtractPack;
+ /// Pref32BitThumb - If true, codegen would prefer 32-bit Thumb instructions
+ /// over 16-bit ones.
+ bool Pref32BitThumb;
+
/// stackAlignment - The minimum alignment known to hold of the stack frame on
/// entry to the function and which must be maintained by every function.
unsigned stackAlignment;
@@ -137,6 +141,7 @@
bool hasT2ExtractPack() const { return HasT2ExtractPack; }
bool useVMLx() const {return hasVFP2() && !SlowVMLx; }
bool isFPBrccSlow() const { return SlowFPBrcc; }
+ bool prefers32BitThumb() const { return Pref32BitThumb; }
bool hasFP16() const { return HasFP16; }
diff --git a/llvm/lib/Target/ARM/ARMTargetMachine.cpp b/llvm/lib/Target/ARM/ARMTargetMachine.cpp
index 2c8460b..ac9b6bf 100644
--- a/llvm/lib/Target/ARM/ARMTargetMachine.cpp
+++ b/llvm/lib/Target/ARM/ARMTargetMachine.cpp
@@ -16,17 +16,11 @@
#include "ARM.h"
#include "llvm/PassManager.h"
#include "llvm/CodeGen/Passes.h"
-#include "llvm/Support/CommandLine.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Target/TargetRegistry.h"
using namespace llvm;
-static cl::opt<bool>
-Prefer32BitThumbInstrs("prefer-32bit-thumb",
- cl::desc("Prefer 32-bit Thumb instructions"),
- cl::init(false));
-
static MCAsmInfo *createMCAsmInfo(const Target &T, StringRef TT) {
Triple TheTriple(TT);
switch (TheTriple.getOS()) {
@@ -143,7 +137,7 @@
bool ARMBaseTargetMachine::addPreEmitPass(PassManagerBase &PM,
CodeGenOpt::Level OptLevel) {
- if (!Prefer32BitThumbInstrs && Subtarget.isThumb2())
+ if (Subtarget.isThumb2() && !Subtarget.prefers32BitThumb())
PM.add(createThumb2SizeReductionPass());
PM.add(createARMConstantIslandPass());