Attachment 43355 Details for Bug 34160 – Path 1/2: Reverts bad commit

[patch] Path 1/2: Reverts bad commit

0001-Revert-glsl-Fix-constant-folding-for-reciprocal-expr.patch (text/plain), 1.95 KB, created by Chad Versace on 2011-02-14 13:46:39 UTC

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Creator: Chad Versace

Created: 2011-02-14 13:46:39 UTC

Size: 1.95 KB

patch

obsolete

>From 1cbce35749e8a72dd36be0be3c3af72cd7269cfa Mon Sep 17 00:00:00 2001
>From: Chad Versace <chad.versace@intel.com>
>Date: Mon, 14 Feb 2011 11:16:42 -0800
>Subject: [PATCH 1/2] Revert "glsl: Fix constant-folding for reciprocal expressions"
>
>This reverts commit b3cf92aa916ee0537ee37723c23a9897ac9cd3e0.
>
>The reverted commit prevented constant-folding of reciprocal expressions
>when the reciprocated expression was 0. However, since the spec allows
>division by zero, constant-folding *is* permissible in this case.
>
>From Section 5.9 of the GLSL 1.20 spec:
>    Dividing by zero does not cause an exception but does result in an
>    unspecified value.
>---
> src/glsl/ir_constant_expression.cpp |   16 ++++++----------
> 1 files changed, 6 insertions(+), 10 deletions(-)
>
>diff --git a/src/glsl/ir_constant_expression.cpp b/src/glsl/ir_constant_expression.cpp
>index 2841fb3..7e00db6 100644
>--- a/src/glsl/ir_constant_expression.cpp
>+++ b/src/glsl/ir_constant_expression.cpp
>@@ -288,24 +288,20 @@ ir_expression::constant_expression_value()
>       break;
> 
>    case ir_unop_rcp:
>-      /* FINISHME: Emit warning when division-by-zero is detected. */
>       assert(op[0]->type->base_type == GLSL_TYPE_FLOAT);
>       for (unsigned c = 0; c < op[0]->type->components(); c++) {
> 	 switch (this->type->base_type) {
> 	 case GLSL_TYPE_UINT:
>-	    if (op[0]->value.u[c] == 0.0)
>-	       return NULL;
>-	    data.u[c] = 1 / op[0]->value.u[c];
>+	    if (op[0]->value.u[c] != 0.0)
>+	       data.u[c] = 1 / op[0]->value.u[c];
> 	    break;
> 	 case GLSL_TYPE_INT:
>-	    if (op[0]->value.i[c] == 0.0)
>-	       return NULL;
>-	    data.i[c] = 1 / op[0]->value.i[c];
>+	    if (op[0]->value.i[c] != 0.0)
>+	       data.i[c] = 1 / op[0]->value.i[c];
> 	    break;
> 	 case GLSL_TYPE_FLOAT:
>-	    if (op[0]->value.f[c] == 0.0)
>-	       return NULL;
>-	    data.f[c] = 1.0F / op[0]->value.f[c];
>+	    if (op[0]->value.f[c] != 0.0)
>+	       data.f[c] = 1.0F / op[0]->value.f[c];
> 	    break;
> 	 default:
> 	    assert(0);
>-- 
>1.7.3.5
>

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