Registers that are used inside of loops need to be considered live
starting with the very first instruction in the loop.
This fixes the following piglit tests on r300:
- glsl-fs-loop-redundant-condition
- glsl-vs-loop-redundant-condition
- glsl-vs-vec4-indexing-temp-dst-in-loop
NOTE: This is a candidate for the 7.9 and 7.10 branches.
---
src/mesa/program/prog_optimize.c | 17 ++++++++++++++---
1 files changed, 14 insertions(+), 3 deletions(-)
diff --git a/src/mesa/program/prog_optimize.c b/src/mesa/program/prog_optimize.c
index 96971f2..164297a 100644
--- a/src/mesa/program/prog_optimize.c
+++ b/src/mesa/program/prog_optimize.c
@@ -937,24 +937,35 @@ update_interval(GLint intBegin[], GLint intEnd[],
GLuint index, GLuint ic)
{
int i;
+ GLuint begin = ic;
+ GLuint end = ic;
/* If the register is used in a loop, extend its lifetime through the end
* of the outermost loop that doesn't contain its definition.
*/
for (i = 0; i < loopStackDepth; i++) {
if (intBegin[index] < loopStack[i].Start) {
- ic = loopStack[i].End;
+ end = loopStack[i].End;
break;
}
}
+ /* Variables that are live at the end of a loop will also be live at the
+ * beginning, so an instruction inside of a loop should have its live
+ * interval begin at the start of the outermost loop.
+ */
+ if (loopStackDepth > 0 && ic > loopStack[0].Start && ic < loopStack[0].End)
{
+ begin = loopStack[0].Start;
+ }
+
ASSERT(index < REG_ALLOCATE_MAX_PROGRAM_TEMPS);
if (intBegin[index] == -1) {
ASSERT(intEnd[index] == -1);
- intBegin[index] = intEnd[index] = ic;
+ intBegin[index] = begin;
+ intEnd[index] = end;
}
else {
- intEnd[index] = ic;
+ intEnd[index] = end;
}
}
--
1.7.3.4
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