[llvm] r196102 - ARM: decide whether to use movw/movt based on "minsize" attribute.
Tim Northover
tnorthover at apple.com
Mon Dec 2 06:46:26 PST 2013
Author: tnorthover
Date: Mon Dec 2 08:46:26 2013
New Revision: 196102
URL: http://llvm.org/viewvc/llvm-project?rev=196102&view=rev
Log:
ARM: decide whether to use movw/movt based on "minsize" attribute.
Added:
llvm/trunk/test/CodeGen/ARM/minsize-litpools.ll
Modified:
llvm/trunk/lib/Target/ARM/ARMBaseInstrInfo.cpp
llvm/trunk/lib/Target/ARM/ARMBaseInstrInfo.h
llvm/trunk/lib/Target/ARM/ARMFrameLowering.cpp
llvm/trunk/lib/Target/ARM/ARMISelLowering.cpp
llvm/trunk/lib/Target/ARM/ARMSubtarget.cpp
llvm/trunk/lib/Target/ARM/ARMSubtarget.h
llvm/trunk/lib/Target/ARM/Thumb1FrameLowering.cpp
llvm/trunk/lib/Target/ARM/Thumb2SizeReduction.cpp
Modified: llvm/trunk/lib/Target/ARM/ARMBaseInstrInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMBaseInstrInfo.cpp?rev=196102&r1=196101&r2=196102&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMBaseInstrInfo.cpp (original)
+++ llvm/trunk/lib/Target/ARM/ARMBaseInstrInfo.cpp Mon Dec 2 08:46:26 2013
@@ -1859,12 +1859,12 @@ void llvm::emitARMRegPlusImmediate(Machi
}
}
-bool llvm::tryFoldSPUpdateIntoPushPop(MachineFunction &MF,
- MachineInstr *MI,
+bool llvm::tryFoldSPUpdateIntoPushPop(const ARMSubtarget &Subtarget,
+ MachineFunction &MF, MachineInstr *MI,
unsigned NumBytes) {
// This optimisation potentially adds lots of load and store
// micro-operations, it's only really a great benefit to code-size.
- if (!MF.getFunction()->hasFnAttribute(Attribute::MinSize))
+ if (!Subtarget.isMinSize())
return false;
// If only one register is pushed/popped, LLVM can use an LDR/STR
Modified: llvm/trunk/lib/Target/ARM/ARMBaseInstrInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMBaseInstrInfo.h?rev=196102&r1=196101&r2=196102&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMBaseInstrInfo.h (original)
+++ llvm/trunk/lib/Target/ARM/ARMBaseInstrInfo.h Mon Dec 2 08:46:26 2013
@@ -417,7 +417,8 @@ void emitThumbRegPlusImmediate(MachineBa
/// NumBytes. This can save a few bytes per function in code-size, but
/// obviously generates more memory traffic. As such, it only takes
/// effect in functions being optimised for size.
-bool tryFoldSPUpdateIntoPushPop(MachineFunction &MF, MachineInstr *MI,
+bool tryFoldSPUpdateIntoPushPop(const ARMSubtarget &Subtarget,
+ MachineFunction &MF, MachineInstr *MI,
unsigned NumBytes);
/// rewriteARMFrameIndex / rewriteT2FrameIndex -
Modified: llvm/trunk/lib/Target/ARM/ARMFrameLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMFrameLowering.cpp?rev=196102&r1=196101&r2=196102&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMFrameLowering.cpp (original)
+++ llvm/trunk/lib/Target/ARM/ARMFrameLowering.cpp Mon Dec 2 08:46:26 2013
@@ -256,7 +256,7 @@ void ARMFrameLowering::emitPrologue(Mach
if (NumBytes) {
// Adjust SP after all the callee-save spills.
- if (tryFoldSPUpdateIntoPushPop(MF, LastPush, NumBytes))
+ if (tryFoldSPUpdateIntoPushPop(STI, MF, LastPush, NumBytes))
FramePtrOffsetInPush += NumBytes;
else
emitSPUpdate(isARM, MBB, MBBI, dl, TII, -NumBytes,
@@ -434,7 +434,8 @@ void ARMFrameLowering::emitEpilogue(Mach
ARM::SP)
.addReg(FramePtr));
}
- } else if (NumBytes && !tryFoldSPUpdateIntoPushPop(MF, FirstPop, NumBytes))
+ } else if (NumBytes &&
+ !tryFoldSPUpdateIntoPushPop(STI, MF, FirstPop, NumBytes))
emitSPUpdate(isARM, MBB, MBBI, dl, TII, NumBytes);
// Increment past our save areas.
Modified: llvm/trunk/lib/Target/ARM/ARMISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMISelLowering.cpp?rev=196102&r1=196101&r2=196102&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/ARM/ARMISelLowering.cpp Mon Dec 2 08:46:26 2013
@@ -1745,8 +1745,7 @@ ARMTargetLowering::LowerCall(TargetLower
// FIXME: handle tail calls differently.
unsigned CallOpc;
- bool HasMinSizeAttr = MF.getFunction()->getAttributes().
- hasAttribute(AttributeSet::FunctionIndex, Attribute::MinSize);
+ bool HasMinSizeAttr = Subtarget->isMinSize();
if (Subtarget->isThumb()) {
if ((!isDirect || isARMFunc) && !Subtarget->hasV5TOps())
CallOpc = ARMISD::CALL_NOLINK;
Modified: llvm/trunk/lib/Target/ARM/ARMSubtarget.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMSubtarget.cpp?rev=196102&r1=196101&r2=196102&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMSubtarget.cpp (original)
+++ llvm/trunk/lib/Target/ARM/ARMSubtarget.cpp Mon Dec 2 08:46:26 2013
@@ -102,6 +102,7 @@ void ARMSubtarget::initializeEnvironment
HasVFPv4 = false;
HasFPARMv8 = false;
HasNEON = false;
+ MinSize = false;
UseNEONForSinglePrecisionFP = false;
UseMulOps = UseFusedMulOps;
SlowFPVMLx = false;
@@ -151,6 +152,9 @@ void ARMSubtarget::resetSubtargetFeature
initializeEnvironment();
resetSubtargetFeatures(CPU, FS);
}
+
+ MinSize =
+ FnAttrs.hasAttribute(AttributeSet::FunctionIndex, Attribute::MinSize);
}
void ARMSubtarget::resetSubtargetFeatures(StringRef CPU, StringRef FS) {
Modified: llvm/trunk/lib/Target/ARM/ARMSubtarget.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMSubtarget.h?rev=196102&r1=196101&r2=196102&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMSubtarget.h (original)
+++ llvm/trunk/lib/Target/ARM/ARMSubtarget.h Mon Dec 2 08:46:26 2013
@@ -64,6 +64,10 @@ protected:
bool HasFPARMv8;
bool HasNEON;
+ /// MinSize - True if the function being compiled has the "minsize" attribute
+ /// and should be optimised for size at the expense of speed.
+ bool MinSize;
+
/// UseNEONForSinglePrecisionFP - if the NEONFP attribute has been
/// specified. Use the method useNEONForSinglePrecisionFP() to
/// determine if NEON should actually be used.
@@ -270,6 +274,7 @@ public:
bool hasCrypto() const { return HasCrypto; }
bool hasCRC() const { return HasCRC; }
bool hasVirtualization() const { return HasVirtualization; }
+ bool isMinSize() const { return MinSize; }
bool useNEONForSinglePrecisionFP() const {
return hasNEON() && UseNEONForSinglePrecisionFP; }
@@ -327,7 +332,7 @@ public:
bool isR9Reserved() const { return IsR9Reserved; }
- bool useMovt() const { return UseMovt && hasV6T2Ops(); }
+ bool useMovt() const { return UseMovt && !isMinSize(); }
bool supportsTailCall() const { return SupportsTailCall; }
bool allowsUnalignedMem() const { return AllowsUnalignedMem; }
Modified: llvm/trunk/lib/Target/ARM/Thumb1FrameLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/Thumb1FrameLowering.cpp?rev=196102&r1=196101&r2=196102&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/Thumb1FrameLowering.cpp (original)
+++ llvm/trunk/lib/Target/ARM/Thumb1FrameLowering.cpp Mon Dec 2 08:46:26 2013
@@ -165,7 +165,7 @@ void Thumb1FrameLowering::emitPrologue(M
NumBytes = DPRCSOffset;
int FramePtrOffsetInBlock = 0;
- if (tryFoldSPUpdateIntoPushPop(MF, prior(MBBI), NumBytes)) {
+ if (tryFoldSPUpdateIntoPushPop(STI, MF, prior(MBBI), NumBytes)) {
FramePtrOffsetInBlock = NumBytes;
NumBytes = 0;
}
@@ -291,9 +291,9 @@ void Thumb1FrameLowering::emitEpilogue(M
&MBB.front() != MBBI &&
prior(MBBI)->getOpcode() == ARM::tPOP) {
MachineBasicBlock::iterator PMBBI = prior(MBBI);
- if (!tryFoldSPUpdateIntoPushPop(MF, PMBBI, NumBytes))
+ if (!tryFoldSPUpdateIntoPushPop(STI, MF, PMBBI, NumBytes))
emitSPUpdate(MBB, PMBBI, TII, dl, *RegInfo, NumBytes);
- } else if (!tryFoldSPUpdateIntoPushPop(MF, MBBI, NumBytes))
+ } else if (!tryFoldSPUpdateIntoPushPop(STI, MF, MBBI, NumBytes))
emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, NumBytes);
}
}
Modified: llvm/trunk/lib/Target/ARM/Thumb2SizeReduction.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/Thumb2SizeReduction.cpp?rev=196102&r1=196101&r2=196102&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/Thumb2SizeReduction.cpp (original)
+++ llvm/trunk/lib/Target/ARM/Thumb2SizeReduction.cpp Mon Dec 2 08:46:26 2013
@@ -1012,8 +1012,7 @@ bool Thumb2SizeReduce::runOnMachineFunct
AttributeSet FnAttrs = MF.getFunction()->getAttributes();
OptimizeSize = FnAttrs.hasAttribute(AttributeSet::FunctionIndex,
Attribute::OptimizeForSize);
- MinimizeSize = FnAttrs.hasAttribute(AttributeSet::FunctionIndex,
- Attribute::MinSize);
+ MinimizeSize = STI->isMinSize();
BlockInfo.clear();
BlockInfo.resize(MF.getNumBlockIDs());
Added: llvm/trunk/test/CodeGen/ARM/minsize-litpools.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/minsize-litpools.ll?rev=196102&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/minsize-litpools.ll (added)
+++ llvm/trunk/test/CodeGen/ARM/minsize-litpools.ll Mon Dec 2 08:46:26 2013
@@ -0,0 +1,26 @@
+; RUN: llc -mtriple=thumbv7s %s -o - | FileCheck %s
+; RUN: llc -mtriple=armv7s %s -o - | FileCheck %s
+
+; CodeGen should be able to set and reset the MinSize subtarget-feature, and
+; make use of it in deciding whether to use MOVW/MOVT for global variables or a
+; lit-pool load (saving roughly 2 bytes of code).
+
+ at var = global i32 0
+
+define i32 @small_global() minsize {
+; CHECK-LABEL: small_global:
+; CHECK: ldr r[[GLOBDEST:[0-9]+]], {{.?LCPI0_0}}
+; CHECK: ldr r0, [r[[GLOBDEST]]]
+
+ %val = load i32* @var
+ ret i32 %val
+}
+
+define i32 @big_global() {
+; CHECK-LABEL: big_global:
+; CHECK: movw [[GLOBDEST:r[0-9]+]], :lower16:var
+; CHECK: movt [[GLOBDEST]], :upper16:var
+
+ %val = load i32* @var
+ ret i32 %val
+}
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