[Mesa-dev] [PATCH v2 3/3] glsl: Use array deref for access to vector components

[Jordan Justen]

On 2015-11-11 20:57:55, Matt Turner wrote:
> On Wed, Nov 11, 2015 at 8:47 PM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> > On Nov 11, 2015 9:10 PM, "Matt Turner" <mattst88 at gmail.com> wrote:
> >>
> >> On Thu, Nov 5, 2015 at 9:44 PM, Kristian Høgsberg Kristensen
> >> <krh at bitplanet.net> wrote:
> >> > diff --git a/src/glsl/ast_function.cpp b/src/glsl/ast_function.cpp
> >> > index e4e4a3f..5584470 100644
> >> > --- a/src/glsl/ast_function.cpp
> >> > +++ b/src/glsl/ast_function.cpp
> >> > @@ -376,12 +368,8 @@ fix_parameter(void *mem_ctx, ir_rvalue *actual,
> >> > const glsl_type *formal_type,
> >> >
> >> >     ir_rvalue *lhs = actual;
> >> >     if (expr != NULL && expr->operation == ir_binop_vector_extract) {
> >> > -      rhs = new(mem_ctx) ir_expression(ir_triop_vector_insert,
> >> > -                                       expr->operands[0]->type,
> >> > -
> >> > expr->operands[0]->clone(mem_ctx, NULL),
> >> > -                                       rhs,
> >> > -
> >> > expr->operands[1]->clone(mem_ctx, NULL));
> >> > -      lhs = expr->operands[0]->clone(mem_ctx, NULL);
> >> > +      lhs == new(mem_ctx)
> >> > ir_dereference_array(expr->operands[0]->clone(mem_ctx, NULL),
> >> > +
> >> > expr->operands[1]->clone(mem_ctx, NULL));
> >>
> >>
> >> I'm getting
> >>
> >> ../../../mesa/src/glsl/ast_function.cpp: In function ‘void
> >> fix_parameter(void*, ir_rvalue*, const glsl_type*, exec_list*,
> >> exec_list*, bool)’:
> >> ../../../mesa/src/glsl/ast_function.cpp:372:88: warning: right operand
> >> of comma operator has no effect [-Wunused-value]
> >>
> >> expr->operands[1]->clone(mem_ctx, NULL));
> >>
> >> from this, but I can't interpret the warning.
> >>
> >
> > Probably one equal sign too many...
> 
> Wow! How it this working?!

It looks like the affected scenario would be calling a function with
an out parameter where the call param is a vector extract.

-Jordan