[PowerPC][RISCV] Attribute 'signext' applied to incompatible type!

[ahatanak]

$ cat test.c

typedef union foo {
  int i;
} foo_t __attribute__((transparent_union));

void test(foo_t a) {
}

$ clang -target powerpc64le-linux -S -o - -emit-llvm test.c
Attribute 'signext' applied to incompatible type!
ptr @test
fatal error: error in backend: Broken module found, compilation aborted!

[llvmbot]

@llvm/issue-subscribers-clang-codegen

Author: Akira Hatanaka (ahatanak)

$ cat test.c ``` typedef union foo { int i; } foo_t __attribute__((transparent_union));

void test(foo_t a) {
}

$ clang -target powerpc64le-linux -S -o - -emit-llvm test.c
Attribute 'signext' applied to incompatible type!
ptr @<!-- -->test
fatal error: error in backend: Broken module found, compilation aborted!
</details>

[llvmbot]

@llvm/issue-subscribers-backend-powerpc

Author: Akira Hatanaka (ahatanak)

$ cat test.c ``` typedef union foo { int i; } foo_t __attribute__((transparent_union));

void test(foo_t a) {
}

$ clang -target powerpc64le-linux -S -o - -emit-llvm test.c
Attribute 'signext' applied to incompatible type!
ptr @<!-- -->test
fatal error: error in backend: Broken module found, compilation aborted!
</details>

[chenzheng1030]

This is really a front end issue.

clang t.c -S -emit-llvm -fno-verify-intermediate-code

%union.foo = type { i32 }

; Function Attrs: noinline nounwind optnone uwtable
define dso_local void @test(%union.foo noundef signext %a.coerce) #0 {
entry:
  %a = alloca %union.foo, align 4
  store %union.foo %a.coerce, ptr %a, align 4
  ret void
}

signext is added to type %union.foo which is not allowed.

[chenzheng1030]

The crash also happens on riscv64. But it is ok on 64 bit targets like aarch64, x86_64. And the good IR is like:

%union.foo = type { i32 }

define dso_local void @test(i32 %0) #0 !dbg !8 {
  %2 = alloca %union.foo, align 4
  %3 = getelementptr inbounds %union.foo, ptr %2, i32 0, i32 0
  store i32 %0, ptr %3, align 4
  call void @llvm.dbg.declare(metadata ptr %2, metadata !18, metadata !DIExpression()), !dbg !19
  ret void, !dbg !20
}

declare void @llvm.dbg.declare(metadata, metadata, metadata) #1

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: Akira Hatanaka (ahatanak)

$ cat test.c ``` typedef union foo { int i; } foo_t __attribute__((transparent_union));

void test(foo_t a) {
}

$ clang -target powerpc64le-linux -S -o - -emit-llvm test.c
Attribute 'signext' applied to incompatible type!
ptr @<!-- -->test
fatal error: error in backend: Broken module found, compilation aborted!
</details>

[lei137]

PR to fix codegen for PowerPC: #101738