Mesa (master): glsl: Fix type error when lowering integer divisions

Paul Berry stereotype441 at kemper.freedesktop.org
Tue Aug 16 11:03:33 PDT 2011


Module: Mesa
Branch: master
Commit: af501e2b29c7fb161671dc5b3395eee1d1b16d3f
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=af501e2b29c7fb161671dc5b3395eee1d1b16d3f

Author: Paul Berry <stereotype441 at gmail.com>
Date:   Fri Aug 12 10:20:34 2011 -0700

glsl: Fix type error when lowering integer divisions

This patch fixes a bug when lowering an integer division:

  x/y

to a multiplication by a reciprocal:

  int(float(x)*reciprocal(float(y)))

If x was a plain int and y was an ivecN, the lowering pass
incorrectly assigned the type of the product to be float, when in fact
it should be vecN.  This caused mesa to abort with an IR validation
error.

Fixes piglit tests {fs,vs}-op-div-int-ivec{2,3,4}.

Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>

---

 src/glsl/lower_instructions.cpp |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/src/glsl/lower_instructions.cpp b/src/glsl/lower_instructions.cpp
index 806f863..23aa19b 100644
--- a/src/glsl/lower_instructions.cpp
+++ b/src/glsl/lower_instructions.cpp
@@ -166,6 +166,10 @@ lower_instructions_visitor::div_to_mul_rcp(ir_expression *ir)
       else
 	 op0 = new(ir) ir_expression(ir_unop_u2f, vec_type, ir->operands[0], NULL);
 
+      vec_type = glsl_type::get_instance(GLSL_TYPE_FLOAT,
+					 ir->type->vector_elements,
+					 ir->type->matrix_columns);
+
       op0 = new(ir) ir_expression(ir_binop_mul, vec_type, op0, op1);
 
       if (ir->operands[1]->type->base_type == GLSL_TYPE_INT) {



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