================
@@ -359,9 +405,158 @@ ABIArgInfo
RISCVABIInfo::coerceAndExpandFPCCEligibleStruct(
return ABIArgInfo::getCoerceAndExpand(CoerceToType, UnpaddedCoerceToType);
}
+bool RISCVABIInfo::detectVLSCCEligibleStruct(QualType Ty, unsigned ABIVLen,
+ llvm::Type *&VLSType) const {
+ // No riscv_vls_cc attribute.
+ if (ABIVLen == 1)
+ return false;
+
+ // Legal struct for VLS calling convention should fulfill following rules:
+ // 1. Struct element should be either "homogeneous fixed-length vectors" or
"a
+ // fixed-length vector array".
+ // 2. Number of struct elements or array elements should be greater or equal
+ // to 1 and less or equal to 8
+ // 3. Total number of vector registers needed should not exceed 8.
+ //
+ // Examples: Assume ABI_VLEN = 128.
+ // These are legal structs:
+ // a. Structs with 1~8 "same" fixed-length vectors, e.g.
+ // struct {
+ // __attribute__((vector_size(16))) int a;
+ // __attribute__((vector_size(16))) int b;
+ // }
+ //
+ // b. Structs with "single" fixed-length vector array with lengh 1~8, e.g.
+ // struct {
+ // __attribute__((vector_size(16))) int a[3];
+ // }
+ // These are illegal structs:
+ // a. Structs with 9 fixed-length vectors, e.g.
+ // struct {
+ // __attribute__((vector_size(16))) int a;
+ // __attribute__((vector_size(16))) int b;
+ // __attribute__((vector_size(16))) int c;
+ // __attribute__((vector_size(16))) int d;
+ // __attribute__((vector_size(16))) int e;
+ // __attribute__((vector_size(16))) int f;
+ // __attribute__((vector_size(16))) int g;
+ // __attribute__((vector_size(16))) int h;
+ // __attribute__((vector_size(16))) int i;
+ // }
+ //
+ // b. Structs with "multiple" fixed-length vector array, e.g.
+ // struct {
+ // __attribute__((vector_size(16))) int a[2];
+ // __attribute__((vector_size(16))) int b[2];
+ // }
+ //
+ // c. Vector registers needed exceeds 8, e.g.
+ // struct {
+ // // Registers needed for single fixed-length element:
+ // // 64 * 8 / ABI_VLEN = 4
+ // __attribute__((vector_size(64))) int a;
+ // __attribute__((vector_size(64))) int b;
+ // __attribute__((vector_size(64))) int c;
+ // __attribute__((vector_size(64))) int d;
+ // }
+ //
+ // Struct of 1 fixed-length vector is passed as a scalable vector.
+ // Struct of >1 fixed-length vectors are passed as vector tuple.
+ // Struct of 1 array of fixed-length vectors is passed as a scalable vector.
+ // Otherwise, pass the struct indirectly.
+
+ if (llvm::StructType *STy = dyn_cast<llvm::StructType>(CGT.ConvertType(Ty)))
{
+ int NumElts = STy->getStructNumElements();
----------------
topperc wrote:
int -> unsigned
https://github.com/llvm/llvm-project/pull/100346
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