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[SOL] Use ADD for subtracting stack pointer #70

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merged 3 commits into from
Dec 12, 2023
Merged

[SOL] Use ADD for subtracting stack pointer #70

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5783903
Use ADD for subtracting stack pointer
LucasSte Dec 8, 2023
ae72364
Adjust variable name
LucasSte Dec 11, 2023
09676d6
Run clang-format
LucasSte Dec 11, 2023
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11 changes: 5 additions & 6 deletions llvm/lib/Target/SBF/SBFFrameLowering.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -16,24 +16,23 @@
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"

using namespace llvm;

namespace {

void adjustStackPointer(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator &MBBI,
unsigned int Opcode) {
bool IsSubtract) {
MachineFrameInfo &MFI = MF.getFrameInfo();
int NumBytes = (int)MFI.getStackSize();
if (NumBytes) {
DebugLoc Dl;
const SBFInstrInfo &TII =
*static_cast<const SBFInstrInfo *>(MF.getSubtarget().getInstrInfo());
BuildMI(MBB, MBBI, Dl, TII.get(Opcode), SBF::R11)
BuildMI(MBB, MBBI, Dl, TII.get(SBF::ADD_ri), SBF::R11)
.addReg(SBF::R11)
.addImm(NumBytes);
.addImm(IsSubtract? -NumBytes : NumBytes);
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Reminder: please be mindful of the LLVM coding conventions[*]. You can run clang-format to help identify/automate correct coding conventions. Upstream LLVM runs this automatically for submitted patches, but we do not yet do this in our local CI.
Also, when you run clang-format on future patches, only commit the diffs that are within the lines of your patch.

[*] See the links in, e.g., https://llvm.org/docs/Contributing.html#how-to-submit-a-patch

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Should I keep a single commit in the PR?

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Yes, you should do a squash commit (with updated log message for the full commit) when done. The github UI will ask you.

}
}

Expand All @@ -47,7 +46,7 @@ void SBFFrameLowering::emitPrologue(MachineFunction &MF,
return;
}
MachineBasicBlock::iterator MBBI = MBB.begin();
adjustStackPointer(MF, MBB, MBBI, SBF::SUB_ri);
adjustStackPointer(MF, MBB, MBBI, true);
}

void SBFFrameLowering::emitEpilogue(MachineFunction &MF,
Expand All @@ -56,7 +55,7 @@ void SBFFrameLowering::emitEpilogue(MachineFunction &MF,
return;
}
MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
adjustStackPointer(MF, MBB, MBBI, SBF::ADD_ri);
adjustStackPointer(MF, MBB, MBBI, false);
}

void SBFFrameLowering::determineCalleeSaves(MachineFunction &MF,
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31 changes: 31 additions & 0 deletions llvm/test/CodeGen/SBF/dynamic_stack_frame_add_not_sub.ll
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@@ -0,0 +1,31 @@
; RUN: llc < %s -march=sbf --mattr=+dynamic-frames | FileCheck %s
;
; Source:
; int test_func(int * vec, int idx) {
; vec[idx] = idx-1;
; return idx;
; }
; Compilation flag:
; clang -S -emit-llvm test.c


; Function Attrs: noinline nounwind optnone ssp uwtable(sync)
define i32 @test_func(ptr noundef %vec, i32 noundef %idx) #0 {
; CHECK-LABEL: test_func:
; CHECK: add64 r11, -16
; CHECK: add64 r11, 16
entry:
%vec.addr = alloca ptr, align 8
%idx.addr = alloca i32, align 4
store ptr %vec, ptr %vec.addr, align 8
store i32 %idx, ptr %idx.addr, align 4
%0 = load i32, ptr %idx.addr, align 4
%sub = sub nsw i32 %0, 1
%1 = load ptr, ptr %vec.addr, align 8
%2 = load i32, ptr %idx.addr, align 4
%idxprom = sext i32 %2 to i64
%arrayidx = getelementptr inbounds i32, ptr %1, i64 %idxprom
store i32 %sub, ptr %arrayidx, align 4
%3 = load i32, ptr %idx.addr, align 4
ret i32 %3
}
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