diff options
| -rw-r--r-- | lib/Target/ARM/ARMFrameLowering.cpp | 19 | ||||
| -rw-r--r-- | lib/Target/ARM/ARMFrameLowering.h | 3 | ||||
| -rw-r--r-- | test/CodeGen/Thumb2/2011-04-21-FILoweringBug.ll | 23 |
3 files changed, 36 insertions, 9 deletions
diff --git a/lib/Target/ARM/ARMFrameLowering.cpp b/lib/Target/ARM/ARMFrameLowering.cpp index c99259df7a..e2e95d47b3 100644 --- a/lib/Target/ARM/ARMFrameLowering.cpp +++ b/lib/Target/ARM/ARMFrameLowering.cpp @@ -445,8 +445,7 @@ ARMFrameLowering::getFrameIndexReference(const MachineFunction &MF, int FI, int ARMFrameLowering::ResolveFrameIndexReference(const MachineFunction &MF, - int FI, - unsigned &FrameReg, + int FI, unsigned &FrameReg, int SPAdj) const { const MachineFrameInfo *MFI = MF.getFrameInfo(); const ARMBaseRegisterInfo *RegInfo = @@ -490,19 +489,23 @@ ARMFrameLowering::ResolveFrameIndexReference(const MachineFunction &MF, return FPOffset; } else if (MFI->hasVarSizedObjects()) { assert(RegInfo->hasBasePointer(MF) && "missing base pointer!"); - // Try to use the frame pointer if we can, else use the base pointer - // since it's available. This is handy for the emergency spill slot, in - // particular. if (AFI->isThumb2Function()) { + // Try to use the frame pointer if we can, else use the base pointer + // since it's available. This is handy for the emergency spill slot, in + // particular. if (FPOffset >= -255 && FPOffset < 0) { FrameReg = RegInfo->getFrameRegister(MF); return FPOffset; } - } else - FrameReg = RegInfo->getBaseRegister(); + } } else if (AFI->isThumb2Function()) { + // Use add <rd>, sp, #<imm8> + // ldr <rd>, [sp, #<imm8>] + // if at all possible to save space. + if (Offset >= 0 && (Offset & 3) == 0 && Offset <= 1020) + return Offset; // In Thumb2 mode, the negative offset is very limited. Try to avoid - // out of range references. + // out of range references. ldr <rt>,[<rn>, #-<imm8>] if (FPOffset >= -255 && FPOffset < 0) { FrameReg = RegInfo->getFrameRegister(MF); return FPOffset; diff --git a/lib/Target/ARM/ARMFrameLowering.h b/lib/Target/ARM/ARMFrameLowering.h index a7b7f15449..61bb8afa40 100644 --- a/lib/Target/ARM/ARMFrameLowering.h +++ b/lib/Target/ARM/ARMFrameLowering.h @@ -51,7 +51,8 @@ public: bool canSimplifyCallFramePseudos(const MachineFunction &MF) const; int getFrameIndexReference(const MachineFunction &MF, int FI, unsigned &FrameReg) const; - int ResolveFrameIndexReference(const MachineFunction &MF, int FI, + int ResolveFrameIndexReference(const MachineFunction &MF, + int FI, unsigned &FrameReg, int SPAdj) const; int getFrameIndexOffset(const MachineFunction &MF, int FI) const; diff --git a/test/CodeGen/Thumb2/2011-04-21-FILoweringBug.ll b/test/CodeGen/Thumb2/2011-04-21-FILoweringBug.ll new file mode 100644 index 0000000000..604a352baa --- /dev/null +++ b/test/CodeGen/Thumb2/2011-04-21-FILoweringBug.ll @@ -0,0 +1,23 @@ +; RUN: llc < %s -mtriple=thumbv7-apple-darwin | FileCheck %s + +; Use sp, #imm to lower frame indices when the offset is multiple of 4 +; and in the range of 0-1020. This saves code size by utilizing +; 16-bit instructions. +; rdar://9321541 + +define i32 @t() nounwind { +entry: +; CHECK: t: +; CHECK: sub sp, #12 +; CHECK-NOT: sub +; CHECK: add r0, sp, #4 +; CHECK: add r1, sp, #8 +; CHECK: mov r2, sp + %size = alloca i32, align 4 + %count = alloca i32, align 4 + %index = alloca i32, align 4 + %0 = call i32 @foo(i32* %count, i32* %size, i32* %index) nounwind + ret i32 %0 +} + +declare i32 @foo(i32*, i32*, i32*) |