[llvm-commits] [llvm] r160695 - in /llvm/trunk: include/llvm/Attributes.h test/CodeGen/X86/inreg.ll

[Duncan Sands]

Hi Rafael, are you sure that this is correct?  Sret has some pretty funky
semantics.  What is the effect of this on generated code and ABI conformance?

Ciao, Duncan.

On 24/07/12 23:40, Rafael Espindola wrote:
> Author: rafael
> Date: Tue Jul 24 16:40:17 2012
> New Revision: 160695
>
> URL: http://llvm.org/viewvc/llvm-project?rev=160695&view=rev
> Log:
> In order to correctly compile
>
> struct s {
>    double x1;
>    float x2;
> };
> __attribute__((regparm(3))) struct s f(int a, int b, int c);
> void g(void) {
>    f(41, 42, 43);
> }
>
> We need to be able to represent passing the address of s to f (sret) in a
> register (inreg). Turns out that all that is needed is to not mark them as
> mutually incompatible.
>
> Added:
>      llvm/trunk/test/CodeGen/X86/inreg.ll
> Modified:
>      llvm/trunk/include/llvm/Attributes.h
>
> Modified: llvm/trunk/include/llvm/Attributes.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Attributes.h?rev=160695&r1=160694&r2=160695&view=diff
> ==============================================================================
> --- llvm/trunk/include/llvm/Attributes.h (original)
> +++ llvm/trunk/include/llvm/Attributes.h Tue Jul 24 16:40:17 2012
> @@ -165,8 +165,9 @@
>   const AttrConst VarArgsIncompatible = {StructRet_i};
>
>   /// @brief Attributes that are mutually incompatible.
> -const AttrConst MutuallyIncompatible[4] = {
> -  {ByVal_i | InReg_i | Nest_i | StructRet_i},
> +const AttrConst MutuallyIncompatible[5] = {
> +  {ByVal_i | Nest_i | StructRet_i},
> +  {ByVal_i | Nest_i | InReg_i },
>     {ZExt_i  | SExt_i},
>     {ReadNone_i | ReadOnly_i},
>     {NoInline_i | AlwaysInline_i}
>
> Added: llvm/trunk/test/CodeGen/X86/inreg.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/inreg.ll?rev=160695&view=auto
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/inreg.ll (added)
> +++ llvm/trunk/test/CodeGen/X86/inreg.ll Tue Jul 24 16:40:17 2012
> @@ -0,0 +1,19 @@
> +; RUN: llc < %s -march=x86 | FileCheck %s
> +
> +%struct.s = type { double, float }
> +
> +define void @g() nounwind {
> +entry:
> +  %tmp = alloca %struct.s, align 4
> +  call void @f(%struct.s* inreg sret %tmp, i32 inreg 41, i32 inreg 42, i32 43)
> +  ret void
> +  ; CHECK: g:
> +  ; CHECK: subl {{.*}}, %esp
> +  ; CHECK-NEXT: $43, (%esp)
> +  ; CHECK-NEXT: leal    16(%esp), %eax
> +  ; CHECK-NEXT: movl    $41, %edx
> +  ; CHECK-NEXT: movl    $42, %ecx
> +  ; CHECK-NEXT: calll   f
> +}
> +
> +declare void @f(%struct.s* inreg sret, i32 inreg, i32 inreg, i32)
>
>
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