diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp --- a/clang/lib/CodeGen/CGCall.cpp +++ b/clang/lib/CodeGen/CGCall.cpp @@ -5743,6 +5743,20 @@ llvm_unreachable("bad evaluation kind"); } + // If coercing a fixed vector from a scalable vector for ABI + // compatibility, and the types match, use the llvm.vector.extract + // intrinsic to perform the conversion. + if (auto *FixedDst = dyn_cast(RetIRTy)) { + llvm::Value *V = CI; + if (auto *ScalableSrc = dyn_cast(V->getType())) { + if (FixedDst->getElementType() == ScalableSrc->getElementType()) { + llvm::Value *Zero = llvm::Constant::getNullValue(CGM.Int64Ty); + V = Builder.CreateExtractVector(FixedDst, V, Zero, "cast.fixed"); + return RValue::get(V); + } + } + } + Address DestPtr = ReturnValue.getValue(); bool DestIsVolatile = ReturnValue.isVolatile(); diff --git a/clang/test/CodeGen/attr-arm-sve-vector-bits-call.c b/clang/test/CodeGen/attr-arm-sve-vector-bits-call.c --- a/clang/test/CodeGen/attr-arm-sve-vector-bits-call.c +++ b/clang/test/CodeGen/attr-arm-sve-vector-bits-call.c @@ -41,11 +41,7 @@ // CHECK-LABEL: @sizeless_caller( // CHECK-NEXT: entry: -// CHECK-NEXT: [[COERCE1:%.*]] = alloca <16 x i32>, align 16 -// CHECK-NEXT: store [[X:%.*]], ptr [[COERCE1]], align 16 -// CHECK-NEXT: [[TMP1:%.*]] = load <16 x i32>, ptr [[COERCE1]], align 16, !tbaa [[TBAA6:![0-9]+]] -// CHECK-NEXT: [[CASTSCALABLESVE2:%.*]] = tail call @llvm.vector.insert.nxv4i32.v16i32( undef, <16 x i32> [[TMP1]], i64 0) -// CHECK-NEXT: ret [[CASTSCALABLESVE2]] +// CHECK-NEXT: ret [[X:%.*]] // svint32_t sizeless_caller(svint32_t x) { return fixed_callee(x); diff --git a/clang/test/CodeGen/attr-riscv-rvv-vector-bits-call.c b/clang/test/CodeGen/attr-riscv-rvv-vector-bits-call.c --- a/clang/test/CodeGen/attr-riscv-rvv-vector-bits-call.c +++ b/clang/test/CodeGen/attr-riscv-rvv-vector-bits-call.c @@ -38,11 +38,7 @@ // CHECK-LABEL: @sizeless_caller( // CHECK-NEXT: entry: -// CHECK-NEXT: [[COERCE1:%.*]] = alloca <8 x i32>, align 8 -// CHECK-NEXT: store [[X:%.*]], ptr [[COERCE1]], align 8 -// CHECK-NEXT: [[TMP0:%.*]] = load <8 x i32>, ptr [[COERCE1]], align 8, !tbaa [[TBAA4:![0-9]+]] -// CHECK-NEXT: [[CASTSCALABLESVE2:%.*]] = tail call @llvm.vector.insert.nxv2i32.v8i32( undef, <8 x i32> [[TMP0]], i64 0) -// CHECK-NEXT: ret [[CASTSCALABLESVE2]] +// CHECK-NEXT: ret [[X:%.*]] // vint32m1_t sizeless_caller(vint32m1_t x) { return fixed_callee(x);