[Mesa-dev] [PATCH] glsl: Fix loop bounds detection.

Paul Berry stereotype441 at gmail.com
Mon Jan 7 18:23:37 PST 2013


When analyzing a loop where the loop condition is expressed in the
non-standard order (e.g. "4 > i" instead of "i < 4"), we were
reversing the condition incorrectly, leading to a loop bound that was
off by 1.

Fixes piglit tests {vs,fs}-loop-bounds-unrolled.shader_test.
---
 src/glsl/loop_controls.cpp | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/glsl/loop_controls.cpp b/src/glsl/loop_controls.cpp
index 9acbadc..79c8204 100644
--- a/src/glsl/loop_controls.cpp
+++ b/src/glsl/loop_controls.cpp
@@ -222,10 +222,10 @@ loop_control_visitor::visit_leave(ir_loop *ir)
 	    limit = cond->operands[0]->as_constant();
 
 	    switch (cmp) {
-	    case ir_binop_less:    cmp = ir_binop_gequal;  break;
-	    case ir_binop_greater: cmp = ir_binop_lequal;  break;
-	    case ir_binop_lequal:  cmp = ir_binop_greater; break;
-	    case ir_binop_gequal:  cmp = ir_binop_less;    break;
+	    case ir_binop_less:    cmp = ir_binop_greater; break;
+	    case ir_binop_greater: cmp = ir_binop_less;    break;
+	    case ir_binop_lequal:  cmp = ir_binop_gequal;  break;
+	    case ir_binop_gequal:  cmp = ir_binop_lequal;  break;
 	    default: assert(!"Should not get here.");
 	    }
 	 }
-- 
1.8.1



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