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Add emulation of (s/u)_(add/sub)_sat intrinsics if needed #2138

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84d448e
Add emulation of {s/u)_(add/sub)_sat intrinsics if needed
MrSidims Jul 20, 2023
56bfd0b
format
MrSidims Aug 25, 2023
196464d
Address comments and fix uadd
MrSidims Aug 28, 2023
15705fa
Fix test
MrSidims Aug 28, 2023
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13 changes: 13 additions & 0 deletions include/LLVMSPIRVOpts.h
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Original file line number Diff line number Diff line change
Expand Up @@ -193,6 +193,14 @@ class TranslatorOpts {
ReplaceLLVMFmulAddWithOpenCLMad = Value;
}

void setUseOpenCLExtInstructionsForLLVMIntrinsic(bool Value) noexcept {
UseOpenCLExtInstructionsForLLVMIntrinsic = Value;
}

bool shouldUseOpenCLExtInstructionsForLLVMIntrinsic() const noexcept {
return UseOpenCLExtInstructionsForLLVMIntrinsic;
}

bool shouldPreserveOCLKernelArgTypeMetadataThroughString() const noexcept {
return PreserveOCLKernelArgTypeMetadataThroughString;
}
Expand Down Expand Up @@ -243,6 +251,11 @@ class TranslatorOpts {
// extended instruction set or with a simple fmul + fadd
bool ReplaceLLVMFmulAddWithOpenCLMad = true;

// Controls whether llvm math intrinsics should be replaced with instructions
// from OpenCL extended instruction set or emulated by native SPIR-V
// instructions
bool UseOpenCLExtInstructionsForLLVMIntrinsic = true;

// Add a workaround to preserve OpenCL kernel_arg_type and
// kernel_arg_type_qual metadata through OpString
bool PreserveOCLKernelArgTypeMetadataThroughString = false;
Expand Down
134 changes: 120 additions & 14 deletions lib/SPIRV/SPIRVWriter.cpp
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Expand Up @@ -3860,21 +3860,127 @@ SPIRVValue *LLVMToSPIRVBase::transIntrinsicInst(IntrinsicInst *II,
case Intrinsic::usub_sat:
case Intrinsic::sadd_sat:
case Intrinsic::ssub_sat: {
SPIRVWord ExtOp;
if (IID == Intrinsic::uadd_sat)
ExtOp = OpenCLLIB::UAdd_sat;
else if (IID == Intrinsic::usub_sat)
ExtOp = OpenCLLIB::USub_sat;
else if (IID == Intrinsic::sadd_sat)
ExtOp = OpenCLLIB::SAdd_sat;
else
ExtOp = OpenCLLIB::SSub_sat;
if (BM->shouldUseOpenCLExtInstructionsForLLVMIntrinsic()) {
SPIRVWord ExtOp;
if (IID == Intrinsic::uadd_sat)
ExtOp = OpenCLLIB::UAdd_sat;
else if (IID == Intrinsic::usub_sat)
ExtOp = OpenCLLIB::USub_sat;
else if (IID == Intrinsic::sadd_sat)
ExtOp = OpenCLLIB::SAdd_sat;
else
ExtOp = OpenCLLIB::SSub_sat;

SPIRVType *Ty = transType(II->getType());
std::vector<SPIRVValue *> Operands = {transValue(II->getArgOperand(0), BB),
transValue(II->getArgOperand(1), BB)};
return BM->addExtInst(Ty, BM->getExtInstSetId(SPIRVEIS_OpenCL), ExtOp,
std::move(Operands), BB);
SPIRVType *Ty = transType(II->getType());
std::vector<SPIRVValue *> Operands = {
transValue(II->getArgOperand(0), BB),
transValue(II->getArgOperand(1), BB)};
return BM->addExtInst(Ty, BM->getExtInstSetId(SPIRVEIS_OpenCL), ExtOp,
std::move(Operands), BB);
}
Type *LLVMTy = II->getType();
SPIRVType *Ty = transType(LLVMTy);
Type *BoolTy = IntegerType::getInt1Ty(M->getContext());
if (auto *VecTy = dyn_cast<VectorType>(LLVMTy))
BoolTy = VectorType::get(BoolTy, VecTy->getElementCount());
SPIRVType *SPVBoolTy = transType(BoolTy);
SPIRVValue *FirstArgVal = transValue(II->getArgOperand(0), BB);
SPIRVValue *SecondArgVal = transValue(II->getArgOperand(1), BB);
if (IID == Intrinsic::uadd_sat) {
// uadd.sat(a, b) -> res = a + b, (res > a) ? res : MAX
SPIRVValue *Max =
transValue(Constant::getAllOnesValue(II->getType()), BB);
SPIRVValue *Add =
BM->addBinaryInst(OpIAdd, Ty, FirstArgVal, SecondArgVal, BB);
SPIRVValue *Cmp = BM->addCmpInst(OpUGreaterThan, SPVBoolTy,
Add, FirstArgVal, BB);
return BM->addSelectInst(Cmp, Add, Max, BB);
}
if (IID == Intrinsic::usub_sat) {
// usub.sat(a, b) -> (a > b) ? a - b : 0
SPIRVValue *Sub =
BM->addBinaryInst(OpISub, Ty, FirstArgVal, SecondArgVal, BB);
SPIRVValue *Cmp = BM->addCmpInst(OpUGreaterThan, SPVBoolTy,
FirstArgVal, SecondArgVal, BB);
SPIRVValue *Zero = transValue(Constant::getNullValue(II->getType()), BB);
return BM->addSelectInst(Cmp, Sub, Zero, BB);
}

uint64_t NumBits = LLVMTy->getScalarSizeInBits();
SPIRVValue *Zero = transValue(Constant::getNullValue(II->getType()), BB);
SPIRVValue *Max =
transValue(Constant::getIntegerValue(
LLVMTy, APInt::getSignedMaxValue(NumBits)), BB);
SPIRVValue *Min =
transValue(Constant::getIntegerValue(
LLVMTy, APInt::getSignedMinValue(NumBits)), BB);
SPIRVValue *IsPositive =
BM->addCmpInst(OpSGreaterThan, SPVBoolTy, SecondArgVal, Zero, BB);
SPIRVValue *IsNegative =
BM->addCmpInst(OpSLessThan, SPVBoolTy, SecondArgVal, Zero, BB);
if (IID == Intrinsic::sadd_sat) {
// sadd.sat(a, b) -> if (b > 0) && a > MAX - b => overflow -> MAX
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@LU-JOHN LU-JOHN Sep 7, 2023 •
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Can we use this sequence:

res = a+b
if (b>0 && a>res) res = MAX
if (b<0 && a<res) res = MIN

This makes it unnecessary to calculate "MAX - b" and "MIN - b"

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@LU-JOHN LU-JOHN Sep 12, 2023 •
edited
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Another implementation with a single comparison:

sum = a+b;
if ( ( ~(a^b)   &   // addends have same sign
       (sum^a)      // result has different sign )
    
     // test MSB
     < 0)
    sum = (0x7fffffff^(a>>31));  // saturated result

// -> else if (b < 0) && a < MIN - b => overflow -> MIN
// -> else a + b
// There two ways to represent such sequence in IR:
// 1. Via 2 branch instructions plus 'phi' instruction;
// 2. Via set of select instructions.
// The later was chosed because of the following consideration:
// speculative branch prediction will most likely consider 'if' statements
// here as always false falling through to 'a + b', and reversing it will
// case performance degradation.
SPIRVValue *Add =
BM->addBinaryInst(OpIAdd, Ty, FirstArgVal, SecondArgVal, BB);

// check if (b > 0) && a > MAX - b condition
SPIRVValue *MaxSubB =
BM->addBinaryInst(OpISub, Ty, Max, SecondArgVal, BB);
SPIRVValue *CanPosOverflow = BM->addCmpInst(OpSGreaterThan, SPVBoolTy,
FirstArgVal, MaxSubB, BB);
SPIRVValue *PosOverflow = BM->addInstTemplate(
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Not sure if the order of the operand could impact performance here. Again just a request for quick check. Not a PR blocker.

Thanks

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TBH I'm not expecting this implementation be performant at all. Ideally we should generate such code that is collapsing to sadd/sub_sat intrinsic after we run InstCombine , but it's not happening. That is because InstCombine checks overflow by extending integer to a larger one and comparing the result with MAX/MIN of the previous type. We can't do this in general case, because we can't cast integer to a wider one in SPIR-V without extensions.

OpLogicalAnd, {CanPosOverflow->getId(), IsPositive->getId()},
BB, SPVBoolTy);

// check if (b < 0) && MIN - b > a condition
SPIRVValue *MinSubB =
BM->addBinaryInst(OpISub, Ty, Min, SecondArgVal, BB);
SPIRVValue *CanNegOverflow = BM->addCmpInst(OpSGreaterThan, SPVBoolTy,
MinSubB, FirstArgVal, BB);
SPIRVValue *NegOverflow = BM->addInstTemplate(
OpLogicalAnd, {CanNegOverflow->getId(), IsNegative->getId()},
BB, SPVBoolTy);

// do selects
SPIRVValue *FirstSelect = BM->addSelectInst(PosOverflow, Max, Add, BB);
return BM->addSelectInst(NegOverflow, Min, FirstSelect, BB);
}
// ssub.sat(a, b) -> if (b > 0) && a < MIN + b => overflow -> MIN
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This can be:

res = a-b
if (b<0 && a>res) res = MAX
if (b>0 && a<res) res = MIN

This makes it unnecessary to calculate "MAX + b" and "MIN + b"

// -> else if (b < 0) && a > MAX + b => overflow -> MAX
// -> else a - b
// still represent via 2 selects
assert(IID == Intrinsic::ssub_sat && "Expected llvm.ssub_sat");
SPIRVValue *Sub =
BM->addBinaryInst(OpISub, Ty, FirstArgVal, SecondArgVal, BB);

// check if (b > 0) && MIN + b > a
SPIRVValue *MinAddB = BM->addBinaryInst(OpIAdd, Ty, Min, SecondArgVal, BB);
SPIRVValue *CanNegOverflow = BM->addCmpInst(OpSGreaterThan, SPVBoolTy,
MinAddB, FirstArgVal, BB);
SPIRVValue *NegOverflow = BM->addInstTemplate(
OpLogicalAnd, {CanNegOverflow->getId(), IsPositive->getId()},
BB, SPVBoolTy);

// check if (b < 0) && a > MAX + b
SPIRVValue *MaxAddB = BM->addBinaryInst(OpIAdd, Ty, Max, SecondArgVal, BB);
SPIRVValue *CanPosOverflow = BM->addCmpInst(OpSGreaterThan, SPVBoolTy,
FirstArgVal, MaxAddB, BB);
SPIRVValue *PosOverflow = BM->addInstTemplate(
OpLogicalAnd, {CanPosOverflow->getId(), IsNegative->getId()},
BB, SPVBoolTy);

// do selects
SPIRVValue *FirstSelect = BM->addSelectInst(PosOverflow, Max, Sub, BB);
return BM->addSelectInst(NegOverflow, Min, FirstSelect, BB);
}
case Intrinsic::memset: {
// Generally there is no direct mapping of memset to SPIR-V. But it turns
Expand Down
4 changes: 4 additions & 0 deletions lib/SPIRV/libSPIRV/SPIRVModule.h
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Expand Up @@ -534,6 +534,10 @@ class SPIRVModule {
return TranslationOpts.shouldReplaceLLVMFmulAddWithOpenCLMad();
}

bool shouldUseOpenCLExtInstructionsForLLVMIntrinsic() const noexcept {
return TranslationOpts.shouldUseOpenCLExtInstructionsForLLVMIntrinsic();
}

bool shouldPreserveOCLKernelArgTypeMetadataThroughString() const noexcept {
return TranslationOpts
.shouldPreserveOCLKernelArgTypeMetadataThroughString();
Expand Down
139 changes: 94 additions & 45 deletions test/llvm-intrinsics/add_sub.sat.ll
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@@ -1,6 +1,16 @@
; RUN: llvm-as < %s -o %t.bc
; RUN: llvm-spirv %t.bc -o %t.spv
; RUN: llvm-spirv %t.spv -to-text -o - | FileCheck %s
; RUN: llvm-spirv %t.spv -to-text -o - | FileCheck %s --check-prefixes=COMMON,OPENCL
; RUN: spirv-val %t.spv

; RUN: llvm-as < %s -o %t.bc
; RUN: llvm-spirv %t.bc --spirv-use-ocl-math-for-llvm-intrinsic=true -o %t.spv
; RUN: llvm-spirv %t.spv -to-text -o - | FileCheck %s --check-prefixes=COMMON,OPENCL
; RUN: spirv-val %t.spv

; RUN: llvm-as < %s -o %t.bc
; RUN: llvm-spirv %t.bc --spirv-use-ocl-math-for-llvm-intrinsic=false -o %t.spv
; RUN: llvm-spirv %t.spv -to-text -o - | FileCheck %s --check-prefixes=COMMON,EMULATION
; RUN: spirv-val %t.spv

; Test checks that saturation addition and substraction llvm intrinsics
Expand All @@ -9,87 +19,126 @@
target datalayout = "e-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024"
target triple = "spir64-unknown-unknown"

; CHECK: ExtInstImport [[ext:[0-9]+]] "OpenCL.std"
; COMMON: ExtInstImport [[ext:[0-9]+]] "OpenCL.std"

; COMMON: Name [[test_uadd:[0-9]+]] "test_uadd"
; COMMON: Name [[test_usub:[0-9]+]] "test_usub"
; COMMON: Name [[test_sadd:[0-9]+]] "test_sadd"
; COMMON: Name [[test_ssub:[0-9]+]] "test_ssub"
; COMMON: Name [[test_vectors:[0-9]+]] "test_vectors"

; CHECK: Name [[test_uadd:[0-9]+]] "test_uadd"
; CHECK: Name [[test_usub:[0-9]+]] "test_usub"
; CHECK: Name [[test_sadd:[0-9]+]] "test_sadd"
; CHECK: Name [[test_ssub:[0-9]+]] "test_ssub"
; CHECK: Name [[test_vectors:[0-9]+]] "test_vectors"
; COMMON-DAG: TypeInt [[int:[0-9]+]] 32 0
; COMMON-DAG: TypeVoid [[void:[0-9]+]]
; COMMON-DAG: TypeVector [[vector:[0-9]+]] [[int]] 4

; CHECK-DAG: TypeInt [[int:[0-9]+]] 32 0
; CHECK-DAG: TypeVoid [[void:[0-9]+]]
; CHECK: TypeVector [[vector:[0-9]+]] [[int]] 4
; EMULATION-DAG: TypeBool [[bool:[0-9]+]]
; EMULATION-DAG: TypeVector [[vector_bool:[0-9]+]] [[bool]] 4
; EMULATION-DAG: Constant [[int]] [[uint_max:[0-9]+]] 4294967295
; EMULATION-DAG: Constant [[int]] [[zero:[0-9]+]] 0
; EMULATION-DAG: Constant [[int]] [[int_max:[0-9]+]] 2147483647
; EMULATION-DAG: Constant [[int]] [[int_min:[0-9]+]] 2147483648
; EMULATION-DAG: ConstantComposite [[vector]] [[vector_uint_max:[0-9]+]] [[uint_max]] [[uint_max]] [[uint_max]] [[uint_max]]

define spir_func void @test_uadd(i32 %a, i32 %b) {
entry:
%0 = call i32 @llvm.uadd.sat.i32(i32 %a, i32 %b)
ret void
}

; CHECK: Function [[void]] [[test_uadd]]
; CHECK-NEXT: FunctionParameter [[int]] [[lhs:[0-9]+]]
; CHECK-NEXT: FunctionParameter [[int]] [[rhs:[0-9]+]]
; CHECK-EMPTY:
; CHECK-NEXT: Label
; CHECK-NEXT: ExtInst [[int]] {{[0-9]+}} [[ext]] u_add_sat [[lhs]] [[rhs]]
; CHECK-NEXT: Return
; COMMON: Function [[void]] [[test_uadd]]
; COMMON-NEXT: FunctionParameter [[int]] [[lhs:[0-9]+]]
; COMMON-NEXT: FunctionParameter [[int]] [[rhs:[0-9]+]]
; COMMON-EMPTY:
; COMMON-NEXT: Label
; OPENCL-NEXT: ExtInst [[int]] {{[0-9]+}} [[ext]] u_add_sat [[lhs]] [[rhs]]
; EMULATION-NEXT: IAdd [[int]] [[add:[0-9]+]] [[lhs]] [[rhs]]
; EMULATION-NEXT: UGreaterThan [[bool]] [[greater:[0-9]+]] [[add]] [[lhs]]
; EMULATION-NEXT: Select [[int]] {{[0-9]+}} [[greater]] [[add]] [[uint_max]]
; COMMON-NEXT: Return

define spir_func void @test_usub(i32 %a, i32 %b) {
entry:
%0 = call i32 @llvm.usub.sat.i32(i32 %a, i32 %b)
ret void
}

; CHECK: Function [[void]] [[test_usub]]
; CHECK-NEXT: FunctionParameter [[int]] [[lhs:[0-9]+]]
; CHECK-NEXT: FunctionParameter [[int]] [[rhs:[0-9]+]]
; CHECK-EMPTY:
; CHECK-NEXT: Label
; CHECK-NEXT: ExtInst [[int]] {{[0-9]+}} [[ext]] u_sub_sat [[lhs]] [[rhs]]
; CHECK-NEXT: Return
; COMMON: Function [[void]] [[test_usub]]
; COMMON-NEXT: FunctionParameter [[int]] [[lhs:[0-9]+]]
; COMMON-NEXT: FunctionParameter [[int]] [[rhs:[0-9]+]]
; COMMON-EMPTY:
; COMMON-NEXT: Label
; OPENCL-NEXT: ExtInst [[int]] {{[0-9]+}} [[ext]] u_sub_sat [[lhs]] [[rhs]]
; EMULATION-NEXT: ISub [[int]] [[sub:[0-9]+]] [[lhs]] [[rhs]]
; EMULATION-NEXT: UGreaterThan [[bool]] [[greater:[0-9]+]] [[lhs]] [[rhs]]
; EMULATION-NEXT: Select [[int]] {{[0-9]+}} [[greater]] [[sub]] [[zero]]
; COMMON-NEXT: Return

define spir_func void @test_sadd(i32 %a, i32 %b) {
entry:
%0 = call i32 @llvm.sadd.sat.i32(i32 %a, i32 %b)
ret void
}

; CHECK: Function [[void]] [[test_sadd]]
; CHECK-NEXT: FunctionParameter [[int]] [[lhs:[0-9]+]]
; CHECK-NEXT: FunctionParameter [[int]] [[rhs:[0-9]+]]
; CHECK-EMPTY:
; CHECK-NEXT: Label
; CHECK-NEXT: ExtInst [[int]] {{[0-9]+}} [[ext]] s_add_sat [[lhs]] [[rhs]]
; CHECK-NEXT: Return
; COMMON: Function [[void]] [[test_sadd]]
; COMMON-NEXT: FunctionParameter [[int]] [[lhs:[0-9]+]]
; COMMON-NEXT: FunctionParameter [[int]] [[rhs:[0-9]+]]
; COMMON-EMPTY:
; COMMON-NEXT: Label
; OPENCL-NEXT: ExtInst [[int]] {{[0-9]+}} [[ext]] s_add_sat [[lhs]] [[rhs]]
; EMULATION-NEXT: SGreaterThan [[bool]] [[greater1:[0-9]+]] [[rhs]] [[zero]]
; EMULATION-NEXT: SLessThan [[bool]] [[less:[0-9]+]] [[rhs]] [[zero]]
; EMULATION-NEXT: IAdd [[int]] [[add:[0-9]+]] [[lhs]] [[rhs]]
; EMULATION-NEXT: ISub [[int]] [[sub1:[0-9]+]] [[int_max]] [[rhs]]
; EMULATION-NEXT: SGreaterThan [[bool]] [[greater2:[0-9]+]] [[lhs]] [[sub1]]
; EMULATION-NEXT: LogicalAnd [[bool]] [[and1:[0-9]+]] [[greater2]] [[greater1]]
; EMULATION-NEXT: ISub [[int]] [[sub2:[0-9]+]] [[int_min]] [[rhs]]
; EMULATION-NEXT: SGreaterThan [[bool]] [[greater3:[0-9]+]] [[sub2]] [[lhs]]
; EMULATION-NEXT: LogicalAnd [[bool]] [[and2:[0-9]+]] [[greater3]] [[less]]
; EMULATION-NEXT: Select [[int]] [[select:[0-9]+]] [[and1]] [[int_max]] [[add]]
; EMULATION-NEXT: Select [[int]] {{[0-9]+}} [[and2]] [[int_min]] [[select]]
; COMMON-NEXT: Return

define spir_func void @test_ssub(i32 %a, i32 %b) {
entry:
%0 = call i32 @llvm.ssub.sat.i32(i32 %a, i32 %b)
ret void
}

; CHECK: Function [[void]] [[test_ssub]]
; CHECK-NEXT: FunctionParameter [[int]] [[lhs:[0-9]+]]
; CHECK-NEXT: FunctionParameter [[int]] [[rhs:[0-9]+]]
; CHECK-EMPTY:
; CHECK-NEXT: Label
; CHECK-NEXT: ExtInst [[int]] {{[0-9]+}} [[ext]] s_sub_sat [[lhs]] [[rhs]]
; CHECK-NEXT: Return
; COMMON: Function [[void]] [[test_ssub]]
; COMMON-NEXT: FunctionParameter [[int]] [[lhs:[0-9]+]]
; COMMON-NEXT: FunctionParameter [[int]] [[rhs:[0-9]+]]
; COMMON-EMPTY:
; COMMON-NEXT: Label
; OPENCL-NEXT: ExtInst [[int]] {{[0-9]+}} [[ext]] s_sub_sat [[lhs]] [[rhs]]
; EMULATION-NEXT: SGreaterThan [[bool]] [[greater1:[0-9]+]] [[rhs]] [[zero]]
; EMULATION-NEXT: SLessThan [[bool]] [[less:[0-9]+]] [[rhs]] [[zero]]
; EMULATION-NEXT: ISub [[int]] [[sub1:[0-9]+]] [[lhs]] [[rhs]]
; EMULATION-NEXT: IAdd [[int]] [[add1:[0-9]+]] [[int_min]] [[rhs]]
; EMULATION-NEXT: SGreaterThan [[bool]] [[greater2:[0-9]+]] [[add1]] [[lhs]]
; EMULATION-NEXT: LogicalAnd [[bool]] [[and1:[0-9]+]] [[greater2]] [[greater1]]
; EMULATION-NEXT: IAdd [[int]] [[add2:[0-9]+]] [[int_max]] [[rhs]]
; EMULATION-NEXT: SGreaterThan [[bool]] [[greater3:[0-9]+]] [[lhs]] [[add2]]
; EMULATION-NEXT: LogicalAnd [[bool]] [[and2:[0-9]+]] [[greater3]] [[less]]
; EMULATION-NEXT: Select [[int]] [[select:[0-9]+]] [[and2]] [[int_max]] [[sub1]]
; EMULATION-NEXT: Select [[int]] {{[0-9]+}} [[and1]] [[int_min]] [[select]]
; COMMON-NEXT: Return

define spir_func void @test_vectors(<4 x i32> %a, <4 x i32> %b) {
entry:
%0 = call <4 x i32> @llvm.uadd.sat.v4i32(<4 x i32> %a, <4 x i32> %b)
ret void
}

; CHECK: Function [[void]] [[test_vectors]]
; CHECK-NEXT: FunctionParameter [[vector]] [[lhs:[0-9]+]]
; CHECK-NEXT: FunctionParameter [[vector]] [[rhs:[0-9]+]]
; CHECK-EMPTY:
; CHECK-NEXT: Label
; CHECK-NEXT: ExtInst [[vector]] {{[0-9]+}} [[ext]] u_add_sat [[lhs]] [[rhs]]
; CHECK-NEXT: Return
; COMMON: Function [[void]] [[test_vectors]]
; COMMON-NEXT: FunctionParameter [[vector]] [[lhs:[0-9]+]]
; COMMON-NEXT: FunctionParameter [[vector]] [[rhs:[0-9]+]]
; COMMON-EMPTY:
; COMMON-NEXT: Label
; OPENCL-NEXT: ExtInst [[vector]] {{[0-9]+}} [[ext]] u_add_sat [[lhs]] [[rhs]]
; EMULATION-NEXT: IAdd [[vector]] [[add:[0-9]+]] [[lhs]] [[rhs]]
; EMULATION-NEXT: UGreaterThan [[vector_bool]] [[greater:[0-9]+]] [[add]] [[lhs]]
; EMULATION-NEXT: Select [[vector]] {{[0-9]+}} [[greater]] [[add]] [[vector_uint_max]]
; COMMON-NEXT: Return

declare i32 @llvm.uadd.sat.i32(i32, i32);
declare i32 @llvm.usub.sat.i32(i32, i32);
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16 changes: 16 additions & 0 deletions tools/llvm-spirv/llvm-spirv.cpp
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Expand Up @@ -258,6 +258,12 @@ static cl::opt<SPIRV::BuiltinFormat> SPIRVBuiltinFormat(
clEnumValN(SPIRV::BuiltinFormat::Global, "global",
"Use globals to represent SPIR-V builtin variables")));

static cl::opt<bool> SPIRVUseOpenCLExtInstructionsForLLVMIntrinsic(
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I feel that this option sounds very generic. It sounds as if every llvm intrinsic is covered under this option. Can you please elaborate?

Thanks

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@MrSidims MrSidims Aug 28, 2023 •
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Renamed to SPIRVUseOpenCLExtInstructionsForLLVMMathIntrinsic

"spirv-use-ocl-math-for-llvm-intrinsic", cl::init(true),
cl::desc("Allow to use OpenCL.ExtendedInstructionSet.100 to translate "
"LLVM math intrinsics. Otherwise use emulation for these "
"intrinsics)"));

static std::string removeExt(const std::string &FileName) {
size_t Pos = FileName.find_last_of(".");
if (Pos != std::string::npos)
Expand Down Expand Up @@ -757,6 +763,16 @@ int main(int Ac, char **Av) {
}
}

if (SPIRVUseOpenCLExtInstructionsForLLVMIntrinsic.getNumOccurrences() != 0) {
if (IsReverse) {
errs() << "Note: --spirv-use-ocl-math-for-llvm-intrinsic option ignored "
"as it only affects translation from LLVM IR to SPIR-V";
} else {
Opts.setUseOpenCLExtInstructionsForLLVMIntrinsic(
SPIRVUseOpenCLExtInstructionsForLLVMIntrinsic);
}
}

if (SPIRVAllowExtraDIExpressions.getNumOccurrences() != 0) {
Opts.setAllowExtraDIExpressionsEnabled(SPIRVAllowExtraDIExpressions);
}
Expand Down