On 7 November 2011 11:12, Ian Romanick <i...@freedesktop.org> wrote:
> From: Ian Romanick <ian.d.roman...@intel.com> > > This prevents other code from seeing a swizzle of the 16th component > of a vector, for example. > > NOTE: This is a candidate for the 7.11 branch. > > Signed-off-by: Ian Romanick <ian.d.roman...@intel.com> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=42517 > --- > src/glsl/lower_vec_index_to_swizzle.cpp | 17 +++++++++++++++-- > 1 files changed, 15 insertions(+), 2 deletions(-) > > diff --git a/src/glsl/lower_vec_index_to_swizzle.cpp > b/src/glsl/lower_vec_index_to_swizzle.cpp > index c7630c2..ebc0833 100644 > --- a/src/glsl/lower_vec_index_to_swizzle.cpp > +++ b/src/glsl/lower_vec_index_to_swizzle.cpp > @@ -33,6 +33,7 @@ > #include "ir_visitor.h" > #include "ir_optimization.h" > #include "glsl_types.h" > +#include "main/macros.h" > > /** > * Visitor class for replacing expressions with ir_constant values. > @@ -76,8 +77,20 @@ > ir_vec_index_to_swizzle_visitor::convert_vec_index_to_swizzle(ir_rvalue *ir) > > void *ctx = ralloc_parent(ir); > this->progress = true; > - return new(ctx) ir_swizzle(deref->array, > - ir_constant->value.i[0], 0, 0, 0, 1); > + > + /* Page 40 of the GLSL 1.20 spec says: > + * > + * "When indexing with non-constant expressions, behavior is > undefined > + * if the index is negative, or greater than or equal to the size > of > + * the vector." > + * > + * The ir_swizzle constructor gets angry if the index is negative or > too > + * large. For simplicity sake, just clamp the index to [0, size-1]. > + */ > + const int i = MIN2(MAX2(ir_constant->value.i[0], 0), > + (deref->array->type->vector_elements - 1)); > + > + return new(ctx) ir_swizzle(deref->array, i, 0, 0, 0, 1); > } > > ir_visitor_status > -- > 1.7.6.4 > > Reviewed-by: Paul Berry <stereotype...@gmail.com>
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