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Diffstat (limited to 'src/gallium/auxiliary/gallivm/lp_bld_quad.c')
-rw-r--r--src/gallium/auxiliary/gallivm/lp_bld_quad.c20
1 files changed, 9 insertions, 11 deletions
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_quad.c b/src/gallium/auxiliary/gallivm/lp_bld_quad.c
index 1955add..f2a762a 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_quad.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_quad.c
@@ -81,7 +81,8 @@ lp_build_ddy(struct lp_build_context *bld,
/*
* Helper for building packed ddx/ddy vector for one coord (scalar per quad
* values). The vector will look like this (8-wide):
- * dr1dx dr1dy _____ _____ dr2dx dr2dy _____ _____
+ * dr1dx _____ -dr1dy _____ dr2dx _____ -dr2dy _____
+ * This only requires one shuffle instead of two for more straightforward packing.
*/
LLVMValueRef
lp_build_packed_ddx_ddy_onecoord(struct lp_build_context *bld,
@@ -91,19 +92,15 @@ lp_build_packed_ddx_ddy_onecoord(struct lp_build_context *bld,
LLVMBuilderRef builder = gallivm->builder;
LLVMValueRef vec1, vec2;
- /* same packing as _twocoord, but can use aos swizzle helper */
+ /* use aos swizzle helper */
- /*
- * XXX could make swizzle1 a noop swizzle by using right top/bottom
- * pair for ddy
- */
- static const unsigned char swizzle1[] = {
- LP_BLD_QUAD_TOP_LEFT, LP_BLD_QUAD_TOP_LEFT,
- LP_BLD_SWIZZLE_DONTCARE, LP_BLD_SWIZZLE_DONTCARE
+ static const unsigned char swizzle1[] = { /* no-op swizzle */
+ LP_BLD_QUAD_TOP_LEFT, LP_BLD_SWIZZLE_DONTCARE,
+ LP_BLD_QUAD_BOTTOM_LEFT, LP_BLD_SWIZZLE_DONTCARE
};
static const unsigned char swizzle2[] = {
- LP_BLD_QUAD_TOP_RIGHT, LP_BLD_QUAD_BOTTOM_LEFT,
- LP_BLD_SWIZZLE_DONTCARE, LP_BLD_SWIZZLE_DONTCARE
+ LP_BLD_QUAD_TOP_RIGHT, LP_BLD_SWIZZLE_DONTCARE,
+ LP_BLD_QUAD_TOP_LEFT, LP_BLD_SWIZZLE_DONTCARE
};
vec1 = lp_build_swizzle_aos(bld, a, swizzle1);
@@ -120,6 +117,7 @@ lp_build_packed_ddx_ddy_onecoord(struct lp_build_context *bld,
* Helper for building packed ddx/ddy vector for one coord (scalar per quad
* values). The vector will look like this (8-wide):
* ds1dx ds1dy dt1dx dt1dy ds2dx ds2dy dt2dx dt2dy
+ * This only needs 2 (v)shufps.
*/
LLVMValueRef
lp_build_packed_ddx_ddy_twocoord(struct lp_build_context *bld,