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[clang][RISCV] Always pass & return flexible array member structs indirectly. #148541

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[clang][RISCV] Always pass & return flexible array member structs indirectly. #148541

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4 changes: 4 additions & 0 deletions clang/lib/CodeGen/Targets/RISCV.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -609,6 +609,10 @@ ABIArgInfo RISCVABIInfo::classifyArgumentType(QualType Ty, bool IsFixed,
if (isEmptyRecord(getContext(), Ty, true) && Size == 0)
return ABIArgInfo::getIgnore();

// Structures with flexible arrays are always indirect.
if (Ty->isStructureTypeWithFlexibleArrayMember())
return getNaturalAlignIndirect(Ty, /*ByVal=*/false);

// Pass floating point values via FPRs if possible.
if (IsFixed && Ty->isFloatingType() && !Ty->isComplexType() &&
FLen >= Size && ArgFPRsLeft) {
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46 changes: 46 additions & 0 deletions clang/test/CodeGen/RISCV/abi-flexible-array-members.cpp
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@@ -0,0 +1,46 @@
// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --filter "^define |^entry:" --version 2
// RUN: %clang_cc1 -x c++ -triple riscv32 -target-feature +f -target-abi ilp32f -emit-llvm %s -o - \
// RUN: | FileCheck -check-prefixes=CHECK32 %s
// RUN: %clang_cc1 -x c++ -triple riscv32 -target-feature +f -target-feature +d -target-abi ilp32d -emit-llvm %s -o - \
// RUN: | FileCheck -check-prefixes=CHECK32 %s
// RUN: %clang_cc1 -x c++ -triple riscv64 -target-feature +f -target-abi lp64f -emit-llvm %s -o - \
// RUN: | FileCheck -check-prefixes=CHECK64 %s
// RUN: %clang_cc1 -x c++ -triple riscv64 -target-feature +f -target-feature +d -target-abi lp64d -emit-llvm %s -o - \
// RUN: | FileCheck -check-prefixes=CHECK64 %s

#include <stdint.h>

// Structs containing C99 flexible array members should always be passed and returned on the stack.

struct s1 {
int a;
int b[];
};

// CHECK32-LABEL: define dso_local void @_Z7test_012s1
// CHECK32-SAME: (ptr dead_on_unwind noalias writable sret([[STRUCT_S1:%.*]]) align 4 [[AGG_RESULT:%.*]], ptr noundef byval([[STRUCT_S1]]) align 4 [[A:%.*]]) #[[ATTR0:[0-9]+]] {
// CHECK32: entry:
//
// CHECK64-LABEL: define dso_local void @_Z7test_012s1
// CHECK64-SAME: (ptr dead_on_unwind noalias writable sret([[STRUCT_S1:%.*]]) align 4 [[AGG_RESULT:%.*]], ptr noundef byval([[STRUCT_S1]]) align 4 [[A:%.*]]) #[[ATTR0:[0-9]+]] {
// CHECK64: entry:
//
struct s1 test_01(struct s1 a) {
return a;
}


// CHECK32-LABEL: define dso_local void @_Z7test_02v
// CHECK32-SAME: (ptr dead_on_unwind noalias writable sret([[STRUCT_S1:%.*]]) align 4 [[AGG_RESULT:%.*]]) #[[ATTR0]] {
// CHECK32: entry:
//
// CHECK64-LABEL: define dso_local void @_Z7test_02v
// CHECK64-SAME: (ptr dead_on_unwind noalias writable sret([[STRUCT_S1:%.*]]) align 4 [[AGG_RESULT:%.*]]) #[[ATTR0]] {
// CHECK64: entry:
//
struct s1 test_02() {
struct s1 r;
r.a = 0;
r.b[0] = 1;
return r;
}
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