[llvm-commits] [llvm] r97071 - in /llvm/trunk: lib/Target/ARM/ARMBaseRegisterInfo.cpp test/CodeGen/Thumb2/2010-02-24-BigStack.ll
Jakob Stoklund Olesen
stoklund at 2pi.dk
Wed Feb 24 14:43:17 PST 2010
Author: stoklund
Date: Wed Feb 24 16:43:17 2010
New Revision: 97071
URL: http://llvm.org/viewvc/llvm-project?rev=97071&view=rev
Log:
Create a stack frame on ARM when
- Function uses all scratch registers AND
- Function does not use any callee saved registers AND
- Stack size is too big to address with immediate offsets.
In this case a register must be scavenged to calculate the address of a stack
object, and the scavenger needs a spare register or emergency spill slot.
Added:
llvm/trunk/test/CodeGen/Thumb2/2010-02-24-BigStack.ll
Modified:
llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.cpp
Modified: llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.cpp?rev=97071&r1=97070&r2=97071&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.cpp (original)
+++ llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.cpp Wed Feb 24 16:43:17 2010
@@ -513,7 +513,7 @@
}
/// estimateStackSize - Estimate and return the size of the frame.
-static unsigned estimateStackSize(MachineFunction &MF, MachineFrameInfo *MFI) {
+static unsigned estimateStackSize(MachineFunction &MF) {
const MachineFrameInfo *FFI = MF.getFrameInfo();
int Offset = 0;
for (int i = FFI->getObjectIndexBegin(); i != 0; ++i) {
@@ -671,8 +671,16 @@
}
}
+ // If any of the stack slot references may be out of range of an immediate
+ // offset, make sure a register (or a spill slot) is available for the
+ // register scavenger. Note that if we're indexing off the frame pointer, the
+ // effective stack size is 4 bytes larger since the FP points to the stack
+ // slot of the previous FP.
+ bool BigStack = RS &&
+ estimateStackSize(MF) + (hasFP(MF) ? 4 : 0) >= estimateRSStackSizeLimit(MF);
+
bool ExtraCSSpill = false;
- if (!CanEliminateFrame || cannotEliminateFrame(MF)) {
+ if (BigStack || !CanEliminateFrame || cannotEliminateFrame(MF)) {
AFI->setHasStackFrame(true);
// If LR is not spilled, but at least one of R4, R5, R6, and R7 is spilled.
@@ -727,51 +735,43 @@
// callee-saved register or reserve a special spill slot to facilitate
// register scavenging. Thumb1 needs a spill slot for stack pointer
// adjustments also, even when the frame itself is small.
- if (RS && !ExtraCSSpill) {
- MachineFrameInfo *MFI = MF.getFrameInfo();
- // If any of the stack slot references may be out of range of an
- // immediate offset, make sure a register (or a spill slot) is
- // available for the register scavenger. Note that if we're indexing
- // off the frame pointer, the effective stack size is 4 bytes larger
- // since the FP points to the stack slot of the previous FP.
- if (estimateStackSize(MF, MFI) + (hasFP(MF) ? 4 : 0)
- >= estimateRSStackSizeLimit(MF)) {
- // If any non-reserved CS register isn't spilled, just spill one or two
- // extra. That should take care of it!
- unsigned NumExtras = TargetAlign / 4;
- SmallVector<unsigned, 2> Extras;
- while (NumExtras && !UnspilledCS1GPRs.empty()) {
- unsigned Reg = UnspilledCS1GPRs.back();
- UnspilledCS1GPRs.pop_back();
+ if (BigStack && !ExtraCSSpill) {
+ // If any non-reserved CS register isn't spilled, just spill one or two
+ // extra. That should take care of it!
+ unsigned NumExtras = TargetAlign / 4;
+ SmallVector<unsigned, 2> Extras;
+ while (NumExtras && !UnspilledCS1GPRs.empty()) {
+ unsigned Reg = UnspilledCS1GPRs.back();
+ UnspilledCS1GPRs.pop_back();
+ if (!isReservedReg(MF, Reg)) {
+ Extras.push_back(Reg);
+ NumExtras--;
+ }
+ }
+ // For non-Thumb1 functions, also check for hi-reg CS registers
+ if (!AFI->isThumb1OnlyFunction()) {
+ while (NumExtras && !UnspilledCS2GPRs.empty()) {
+ unsigned Reg = UnspilledCS2GPRs.back();
+ UnspilledCS2GPRs.pop_back();
if (!isReservedReg(MF, Reg)) {
Extras.push_back(Reg);
NumExtras--;
}
}
- // For non-Thumb1 functions, also check for hi-reg CS registers
- if (!AFI->isThumb1OnlyFunction()) {
- while (NumExtras && !UnspilledCS2GPRs.empty()) {
- unsigned Reg = UnspilledCS2GPRs.back();
- UnspilledCS2GPRs.pop_back();
- if (!isReservedReg(MF, Reg)) {
- Extras.push_back(Reg);
- NumExtras--;
- }
- }
- }
- if (Extras.size() && NumExtras == 0) {
- for (unsigned i = 0, e = Extras.size(); i != e; ++i) {
- MF.getRegInfo().setPhysRegUsed(Extras[i]);
- AFI->setCSRegisterIsSpilled(Extras[i]);
- }
- } else if (!AFI->isThumb1OnlyFunction()) {
- // note: Thumb1 functions spill to R12, not the stack.
- // Reserve a slot closest to SP or frame pointer.
- const TargetRegisterClass *RC = ARM::GPRRegisterClass;
- RS->setScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(),
- RC->getAlignment(),
- false));
+ }
+ if (Extras.size() && NumExtras == 0) {
+ for (unsigned i = 0, e = Extras.size(); i != e; ++i) {
+ MF.getRegInfo().setPhysRegUsed(Extras[i]);
+ AFI->setCSRegisterIsSpilled(Extras[i]);
}
+ } else if (!AFI->isThumb1OnlyFunction()) {
+ // note: Thumb1 functions spill to R12, not the stack. Reserve a slot
+ // closest to SP or frame pointer.
+ const TargetRegisterClass *RC = ARM::GPRRegisterClass;
+ MachineFrameInfo *MFI = MF.getFrameInfo();
+ RS->setScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(),
+ RC->getAlignment(),
+ false));
}
}
}
Added: llvm/trunk/test/CodeGen/Thumb2/2010-02-24-BigStack.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Thumb2/2010-02-24-BigStack.ll?rev=97071&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/Thumb2/2010-02-24-BigStack.ll (added)
+++ llvm/trunk/test/CodeGen/Thumb2/2010-02-24-BigStack.ll Wed Feb 24 16:43:17 2010
@@ -0,0 +1,15 @@
+; RUN: llc < %s -O0 -relocation-model=pic -disable-fp-elim -mcpu=cortex-a8 -mattr=+vfp2
+; This test creates a big stack frame without spilling any callee-saved registers.
+; Make sure the whole stack frame is addrerssable wiothout scavenger crashes.
+target datalayout = "e-p:32:32:32-i1:8:32-i8:8:32-i16:16:32-i32:32:32-i64:32:32-f32:32:32-f64:32:32-v64:64:64-v128:128:128-a0:0:32-n32"
+target triple = "thumbv7-apple-darwin3.0.0-iphoneos"
+
+define arm_apcscc void @FindMin(double* %panelTDEL, i8* %dclOfRow, i32 %numRows, i32 %numCols, double* %retMin_RES_TDEL) {
+entry:
+ %panelTDEL.addr = alloca double*, align 4 ; <double**> [#uses=1]
+ %panelResTDEL = alloca [2560 x double], align 4 ; <[2560 x double]*> [#uses=0]
+ store double* %panelTDEL, double** %panelTDEL.addr
+ store double* %retMin_RES_TDEL, double** undef
+ store i32 0, i32* undef
+ unreachable
+}
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