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[RISCV] Add call preserved regmask to tail calls. (#122181)

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Every call should have regmask operand to indicate what registers are
preserved or clobbered by the call. VirtRegRewriter uses this to tell
MachineRegisterInfo what registers are clobbered by a function. If the
mask isn't present the registers potentially clobbered by a tail called
function aren't counted. I have checked ARM, AArch64, and X86 and they
all have a regmask operand on their tail calls.

I believe this fixes an issue I'm seeing with IPRA.
This commit is contained in:
Craig Topper 2025-01-08 16:19:31 -08:00 committed by GitHub
parent b48b99f625
commit b0f11dfc75
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3 changed files with 7 additions and 9 deletions
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12
llvm/lib/Target/RISCV/RISCVISelLowering.cpp
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@ -20273,13 +20273,11 @@ SDValue RISCVTargetLowering::LowerCall(CallLoweringInfo &CLI,
for (auto &Reg : RegsToPass)
Ops.push_back(DAG.getRegister(Reg.first, Reg.second.getValueType()));
if (!IsTailCall) {
// Add a register mask operand representing the call-preserved registers.
const TargetRegisterInfo *TRI = Subtarget.getRegisterInfo();
const uint32_t *Mask = TRI->getCallPreservedMask(MF, CallConv);
assert(Mask && "Missing call preserved mask for calling convention");
Ops.push_back(DAG.getRegisterMask(Mask));
}
// Add a register mask operand representing the call-preserved registers.
const TargetRegisterInfo *TRI = Subtarget.getRegisterInfo();
const uint32_t *Mask = TRI->getCallPreservedMask(MF, CallConv);
assert(Mask && "Missing call preserved mask for calling convention");
Ops.push_back(DAG.getRegisterMask(Mask));
// Glue the call to the argument copies, if any.
if (Glue.getNode())

2
llvm/test/CodeGen/RISCV/kcfi-isel-mir.ll
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@ -20,7 +20,7 @@ define void @f2(ptr noundef %x) #0 {
; CHECK-NEXT: liveins: $x10
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: [[COPY:%[0-9]+]]:gprtc = COPY $x10
; CHECK-NEXT: PseudoTAILIndirect [[COPY]], implicit $x2, cfi-type 12345678
; CHECK-NEXT: PseudoTAILIndirect [[COPY]], csr_ilp32_lp64, implicit $x2, cfi-type 12345678
tail call void %x() [ "kcfi"(i32 12345678) ]
ret void
}

2
llvm/test/CodeGen/RISCV/kcfi-mir.ll
View File

@ -30,7 +30,7 @@ define void @f2(ptr noundef %x) #0 {
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: BUNDLE implicit-def $x6, implicit-def $x6_w, implicit-def $x6_h, implicit-def $x7, implicit-def $x7_w, implicit-def $x7_h, implicit-def $x28, implicit-def $x28_w, implicit-def $x28_h, implicit-def $x29, implicit-def $x29_w, implicit-def $x29_h, implicit-def $x30, implicit-def $x30_w, implicit-def $x30_h, implicit-def $x31, implicit-def $x31_w, implicit-def $x31_h, implicit killed $x10, implicit $x2 {
; CHECK-NEXT: KCFI_CHECK $x10, 12345678, implicit-def $x6, implicit-def $x7, implicit-def $x28, implicit-def $x29, implicit-def $x30, implicit-def $x31
; CHECK-NEXT: PseudoTAILIndirect killed $x10, implicit $x2
; CHECK-NEXT: PseudoTAILIndirect killed $x10, csr_ilp32_lp64, implicit $x2
; CHECK-NEXT: }
tail call void %x() [ "kcfi"(i32 12345678) ]
ret void