Mesa (master): glsl: Fix constant evaluation of the rcp op.

[Francisco Jerez]

Module: Mesa
Branch: master
Commit: 6643a97de308bc100a497f18fed8819f6f6f570b
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=6643a97de308bc100a497f18fed8819f6f6f570b

Author: Francisco Jerez <currojerez at riseup.net>
Date:   Tue Jan 24 11:41:46 2017 -0800

glsl: Fix constant evaluation of the rcp op.

Will avoid a regression in a future commit that introduces some
additional rcp operations.  According to the GLSL 4.10 specification:

"Dividing by 0 results in the appropriately signed IEEE Inf."

Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>
Reviewed-by: Juan A. Suarez Romero <jasuarez at igalia.com>

---

 src/compiler/glsl/ir_expression_operation.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/glsl/ir_expression_operation.py b/src/compiler/glsl/ir_expression_operation.py
index f91ac9b..4ac1ffb 100644
--- a/src/compiler/glsl/ir_expression_operation.py
+++ b/src/compiler/glsl/ir_expression_operation.py
@@ -422,7 +422,7 @@ ir_expression_operation = [
    operation("neg", 1, source_types=numeric_types, c_expression={'u': "-((int) {src0})", 'default': "-{src0}"}),
    operation("abs", 1, source_types=signed_numeric_types, c_expression={'i': "{src0} < 0 ? -{src0} : {src0}", 'f': "fabsf({src0})", 'd': "fabs({src0})", 'i64': "{src0} < 0 ? -{src0} : {src0}"}),
    operation("sign", 1, source_types=signed_numeric_types, c_expression={'i': "({src0} > 0) - ({src0} < 0)", 'f': "float(({src0} > 0.0F) - ({src0} < 0.0F))", 'd': "double(({src0} > 0.0) - ({src0} < 0.0))", 'i64': "({src0} > 0) - ({src0} < 0)"}),
-   operation("rcp", 1, source_types=real_types, c_expression={'f': "{src0} != 0.0F ? 1.0F / {src0} : 0.0F", 'd': "{src0} != 0.0 ? 1.0 / {src0} : 0.0"}),
+   operation("rcp", 1, source_types=real_types, c_expression={'f': "1.0F / {src0}", 'd': "1.0 / {src0}"}),
    operation("rsq", 1, source_types=real_types, c_expression={'f': "1.0F / sqrtf({src0})", 'd': "1.0 / sqrt({src0})"}),
    operation("sqrt", 1, source_types=real_types, c_expression={'f': "sqrtf({src0})", 'd': "sqrt({src0})"}),
    operation("exp", 1, source_types=(float_type,), c_expression="expf({src0})"),         # Log base e on gentype