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[CIR][X86] Implement xsave/xrstor builtins Fixes part of #167752 #170877

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Merged
andykaylor merged 3 commits into from
Dec 9, 2025
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[CIR][X86] Implement xsave/xrstor builtins Fixes part of #167752 #170877

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e590a91
[CIR][X86] Implement xsave/xrstor builtins Fixes part of #167752
medhatiwari Dec 5, 2025
f53280c
Address review comments
medhatiwari Dec 6, 2025
cc61bb9
Add detailed CIR/LLVM/OGCG checks showing full use-def flow for test_…
medhatiwari Dec 9, 2025
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73 changes: 72 additions & 1 deletion clang/lib/CIR/CodeGen/CIRGenBuiltinX86.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -533,9 +533,80 @@ mlir::Value CIRGenFunction::emitX86BuiltinExpr(unsigned builtinID,
case X86::BI__builtin_ia32_xsaves:
case X86::BI__builtin_ia32_xsaves64:
case X86::BI__builtin_ia32_xsetbv:
case X86::BI_xsetbv:
case X86::BI_xsetbv: {
mlir::Location loc = getLoc(expr->getExprLoc());
StringRef intrinsicName;
switch (builtinID) {
default:
llvm_unreachable("Unexpected builtin");
case X86::BI__builtin_ia32_xsave:
intrinsicName = "x86.xsave";
break;
case X86::BI__builtin_ia32_xsave64:
intrinsicName = "x86.xsave64";
break;
case X86::BI__builtin_ia32_xrstor:
intrinsicName = "x86.xrstor";
break;
case X86::BI__builtin_ia32_xrstor64:
intrinsicName = "x86.xrstor64";
break;
case X86::BI__builtin_ia32_xsaveopt:
intrinsicName = "x86.xsaveopt";
break;
case X86::BI__builtin_ia32_xsaveopt64:
intrinsicName = "x86.xsaveopt64";
break;
case X86::BI__builtin_ia32_xrstors:
intrinsicName = "x86.xrstors";
break;
case X86::BI__builtin_ia32_xrstors64:
intrinsicName = "x86.xrstors64";
break;
case X86::BI__builtin_ia32_xsavec:
intrinsicName = "x86.xsavec";
break;
case X86::BI__builtin_ia32_xsavec64:
intrinsicName = "x86.xsavec64";
break;
case X86::BI__builtin_ia32_xsaves:
intrinsicName = "x86.xsaves";
break;
case X86::BI__builtin_ia32_xsaves64:
intrinsicName = "x86.xsaves64";
break;
case X86::BI__builtin_ia32_xsetbv:
case X86::BI_xsetbv:
intrinsicName = "x86.xsetbv";
break;
}

// The xsave family of instructions take a 64-bit mask that specifies
// which processor state components to save/restore. The hardware expects
// this mask split into two 32-bit registers: EDX (high 32 bits) and
// EAX (low 32 bits).
mlir::Type i32Ty = builder.getSInt32Ty();
mlir::Type i64Ty = builder.getSInt64Ty();

// Mhi = (uint32_t)(ops[1] >> 32) - extract high 32 bits via right shift
cir::ConstantOp shift32 =
builder.getConstant(loc, cir::IntAttr::get(i64Ty, 32));
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@andykaylor andykaylor Dec 5, 2025

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Suggested change
cir::ConstantOp shift32 =
builder.getConstant(loc, cir::IntAttr::get(i64Ty, 32));
cir::ConstantOp shift32 = builder.getSInt64(32, loc);

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@medhatiwari medhatiwari Dec 6, 2025

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Done, changed to builder.getSInt64(32, loc). Also fixed the parameter name to /isShiftLeft=/false for clarity.

mlir::Value mhi =
builder.createShift(loc, ops[1], shift32.getResult(), /*isRight=*/true);
mhi = builder.createIntCast(mhi, i32Ty);

// Mlo = (uint32_t)ops[1] - extract low 32 bits by truncation
mlir::Value mlo = builder.createIntCast(ops[1], i32Ty);

return emitIntrinsicCallOp(builder, loc, intrinsicName, voidTy,
mlir::ValueRange{ops[0], mhi, mlo});
}
case X86::BI__builtin_ia32_xgetbv:
case X86::BI_xgetbv:
// xgetbv reads the extended control register specified by ops[0] (ECX)
// and returns the 64-bit value
return emitIntrinsicCallOp(builder, getLoc(expr->getExprLoc()),
"x86.xgetbv", builder.getUInt64Ty(), ops[0]);
case X86::BI__builtin_ia32_storedqudi128_mask:
case X86::BI__builtin_ia32_storedqusi128_mask:
case X86::BI__builtin_ia32_storedquhi128_mask:
Expand Down
175 changes: 175 additions & 0 deletions clang/test/CIR/CodeGenBuiltins/X86/xsave-builtins.c
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@@ -0,0 +1,175 @@
// RUN: %clang_cc1 -x c -ffreestanding %s -triple=x86_64-unknown-linux -target-feature +xsave -target-feature +xsaveopt -target-feature +xsavec -target-feature +xsaves -fclangir -emit-cir -o %t.cir -Wall -Werror
// RUN: FileCheck --check-prefix=CIR --input-file=%t.cir %s
// RUN: %clang_cc1 -x c -ffreestanding %s -triple=x86_64-unknown-linux -target-feature +xsave -target-feature +xsaveopt -target-feature +xsavec -target-feature +xsaves -fclangir -emit-llvm -o %t.ll -Wall -Werror
// RUN: FileCheck --check-prefixes=LLVM --input-file=%t.ll %s

// RUN: %clang_cc1 -x c -ffreestanding %s -triple=x86_64-unknown-linux -target-feature +xsave -target-feature +xsaveopt -target-feature +xsavec -target-feature +xsaves -emit-llvm -o - -Wall -Werror | FileCheck %s -check-prefix=OGCG

void test_xsave(void *p, unsigned long long m) {
// CIR-LABEL: test_xsave
// CIR: cir.call_llvm_intrinsic "x86.xsave"
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@andykaylor andykaylor Dec 5, 2025

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Can you add checks that show all the casts, shifts, and parameters?

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@medhatiwari medhatiwari Dec 6, 2025

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Added detailed CIR and LLVM checks for test_xsave showing the shift, casts, and intrinsic call with parameters. The pattern is the same for all other xsave variants, so I kept just the intrinsic name check for the rest to avoid redundancy.


// LLVM-LABEL: test_xsave
// LLVM: call void @llvm.x86.xsave

// OGCG-LABEL: test_xsave
// OGCG: call void @llvm.x86.xsave
__builtin_ia32_xsave(p, m);
}

void test_xsave64(void *p, unsigned long long m) {
// CIR-LABEL: test_xsave64
// CIR: cir.call_llvm_intrinsic "x86.xsave64"

// LLVM-LABEL: test_xsave64
// LLVM: call void @llvm.x86.xsave64

// OGCG-LABEL: test_xsave64
// OGCG: call void @llvm.x86.xsave64
__builtin_ia32_xsave64(p, m);
}

void test_xrstor(void *p, unsigned long long m) {
// CIR-LABEL: test_xrstor
// CIR: cir.call_llvm_intrinsic "x86.xrstor"

// LLVM-LABEL: test_xrstor
// LLVM: call void @llvm.x86.xrstor

// OGCG-LABEL: test_xrstor
// OGCG: call void @llvm.x86.xrstor
__builtin_ia32_xrstor(p, m);
}

void test_xrstor64(void *p, unsigned long long m) {
// CIR-LABEL: test_xrstor64
// CIR: cir.call_llvm_intrinsic "x86.xrstor64"

// LLVM-LABEL: test_xrstor64
// LLVM: call void @llvm.x86.xrstor64

// OGCG-LABEL: test_xrstor64
// OGCG: call void @llvm.x86.xrstor64
__builtin_ia32_xrstor64(p, m);
}

void test_xsaveopt(void *p, unsigned long long m) {
// CIR-LABEL: test_xsaveopt
// CIR: cir.call_llvm_intrinsic "x86.xsaveopt"

// LLVM-LABEL: test_xsaveopt
// LLVM: call void @llvm.x86.xsaveopt

// OGCG-LABEL: test_xsaveopt
// OGCG: call void @llvm.x86.xsaveopt
__builtin_ia32_xsaveopt(p, m);
}

void test_xsaveopt64(void *p, unsigned long long m) {
// CIR-LABEL: test_xsaveopt64
// CIR: cir.call_llvm_intrinsic "x86.xsaveopt64"

// LLVM-LABEL: test_xsaveopt64
// LLVM: call void @llvm.x86.xsaveopt64

// OGCG-LABEL: test_xsaveopt64
// OGCG: call void @llvm.x86.xsaveopt64
__builtin_ia32_xsaveopt64(p, m);
}

void test_xsavec(void *p, unsigned long long m) {
// CIR-LABEL: test_xsavec
// CIR: cir.call_llvm_intrinsic "x86.xsavec"

// LLVM-LABEL: test_xsavec
// LLVM: call void @llvm.x86.xsavec

// OGCG-LABEL: test_xsavec
// OGCG: call void @llvm.x86.xsavec
__builtin_ia32_xsavec(p, m);
}

void test_xsavec64(void *p, unsigned long long m) {
// CIR-LABEL: test_xsavec64
// CIR: cir.call_llvm_intrinsic "x86.xsavec64"

// LLVM-LABEL: test_xsavec64
// LLVM: call void @llvm.x86.xsavec64

// OGCG-LABEL: test_xsavec64
// OGCG: call void @llvm.x86.xsavec64
__builtin_ia32_xsavec64(p, m);
}

void test_xsaves(void *p, unsigned long long m) {
// CIR-LABEL: test_xsaves
// CIR: cir.call_llvm_intrinsic "x86.xsaves"

// LLVM-LABEL: test_xsaves
// LLVM: call void @llvm.x86.xsaves

// OGCG-LABEL: test_xsaves
// OGCG: call void @llvm.x86.xsaves
__builtin_ia32_xsaves(p, m);
}

void test_xsaves64(void *p, unsigned long long m) {
// CIR-LABEL: test_xsaves64
// CIR: cir.call_llvm_intrinsic "x86.xsaves64"

// LLVM-LABEL: test_xsaves64
// LLVM: call void @llvm.x86.xsaves64

// OGCG-LABEL: test_xsaves64
// OGCG: call void @llvm.x86.xsaves64
__builtin_ia32_xsaves64(p, m);
}

void test_xrstors(void *p, unsigned long long m) {
// CIR-LABEL: test_xrstors
// CIR: cir.call_llvm_intrinsic "x86.xrstors"

// LLVM-LABEL: test_xrstors
// LLVM: call void @llvm.x86.xrstors

// OGCG-LABEL: test_xrstors
// OGCG: call void @llvm.x86.xrstors
__builtin_ia32_xrstors(p, m);
}

void test_xrstors64(void *p, unsigned long long m) {
// CIR-LABEL: test_xrstors64
// CIR: cir.call_llvm_intrinsic "x86.xrstors64"

// LLVM-LABEL: test_xrstors64
// LLVM: call void @llvm.x86.xrstors64

// OGCG-LABEL: test_xrstors64
// OGCG: call void @llvm.x86.xrstors64
__builtin_ia32_xrstors64(p, m);
}

unsigned long long test_xgetbv(unsigned int a) {
// CIR-LABEL: test_xgetbv
// CIR: cir.call_llvm_intrinsic "x86.xgetbv"

// LLVM-LABEL: test_xgetbv
// LLVM: call i64 @llvm.x86.xgetbv

// OGCG-LABEL: test_xgetbv
// OGCG: call i64 @llvm.x86.xgetbv
return __builtin_ia32_xgetbv(a);
}

void test_xsetbv(unsigned int a, unsigned long long m) {
// CIR-LABEL: test_xsetbv
// CIR: cir.call_llvm_intrinsic "x86.xsetbv"

// LLVM-LABEL: test_xsetbv
// LLVM: call void @llvm.x86.xsetbv

// OGCG-LABEL: test_xsetbv
// OGCG: call void @llvm.x86.xsetbv
__builtin_ia32_xsetbv(a, m);
}

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