[Mesa-dev] [PATCH] glsl: fix lowering conditional returns in subroutines

[Fabian Bieler]

Hello!

My last mail was misleading. The described behaviour (continue out of loop 
etc.) occurs with mesa's current glsl compiler. The attached patch tries to 
fix that.

I appologize for the faulty description and hope it was the cause for the lack 
of feedback to my last mail.

I also attached two piglit tests to demonstrate the bug.

Fabian

On Friday 26 November 2010 02:09:31 Fabian Bieler wrote:
> Hello!
>
> This patch fixes a bug in the lower_jumps pass if lower_sub_return is set
> to true.
>
> Subroutines such as
>
> void sub() {
>   for (int i = 0; i < 2; ++i) {
>     if (i)
>       return;
>   }
> }
>
> a continue instruction is inserted outside of the loop.
>
> Subroutines such as
>
> void sub() {
>   for (int j = 0; j < 2; ++j) {
>     for (int i = 0; i < 2; ++i) {
>       if (i)
>         return;
>     }
>   }
>   alter_some_global_variable();
>   return;
> }
>
> get transformed to
>
> void sub() {
>   bool return_flag = false;
>   for (int j = 0; j < 2; ++j) {
>     for (int i = 0; i < 2; ++i) {
>       if (i) {
>         return_flag = true;
>         break;
>       }
>     }
>     if (return_flag)
>       break;
>   }
>   alter_some_global_variable();
>   return;
> }
>
> Please review
>
> Fabian


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