gallivm: Pass texture coords derivates as scalars.

We end up treating them as scalars in the end, and it saves some
instructions.

1 files changed, 18 insertions, 10 deletions

diff --git a/src/gallium/auxiliary/gallivm/lp_bld_quad.c b/src/gallium/auxiliary/gallivm/lp_bld_quad.c
index 7b1088939b..c18c8b4710 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_quad.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_quad.c
@@ -81,11 +81,15 @@ LLVMValueRef
 lp_build_scalar_ddx(struct lp_build_context *bld,
                     LLVMValueRef a)
 {
-   LLVMValueRef idx_left  = LLVMConstInt(LLVMInt32Type(), LP_BLD_QUAD_TOP_LEFT, 0);
-   LLVMValueRef idx_right = LLVMConstInt(LLVMInt32Type(), LP_BLD_QUAD_TOP_RIGHT, 0);
-   LLVMValueRef a_left  = LLVMBuildExtractElement(bld->builder, a, idx_left, "");
-   LLVMValueRef a_right = LLVMBuildExtractElement(bld->builder, a, idx_right, "");
-   return lp_build_sub(bld, a_right, a_left);
+   LLVMTypeRef i32t = LLVMInt32Type();
+   LLVMValueRef idx_left  = LLVMConstInt(i32t, LP_BLD_QUAD_TOP_LEFT, 0);
+   LLVMValueRef idx_right = LLVMConstInt(i32t, LP_BLD_QUAD_TOP_RIGHT, 0);
+   LLVMValueRef a_left  = LLVMBuildExtractElement(bld->builder, a, idx_left, "left");
+   LLVMValueRef a_right = LLVMBuildExtractElement(bld->builder, a, idx_right, "right");
+   if (bld->type.floating)
+      return LLVMBuildFSub(bld->builder, a_right, a_left, "ddx");
+   else
+      return LLVMBuildSub(bld->builder, a_right, a_left, "ddx");
 }
 
 
@@ -93,9 +97,13 @@ LLVMValueRef
 lp_build_scalar_ddy(struct lp_build_context *bld,
                     LLVMValueRef a)
 {
-   LLVMValueRef idx_top    = LLVMConstInt(LLVMInt32Type(), LP_BLD_QUAD_TOP_LEFT, 0);
-   LLVMValueRef idx_bottom = LLVMConstInt(LLVMInt32Type(), LP_BLD_QUAD_BOTTOM_LEFT, 0);
-   LLVMValueRef a_top    = LLVMBuildExtractElement(bld->builder, a, idx_top, "");
-   LLVMValueRef a_bottom = LLVMBuildExtractElement(bld->builder, a, idx_bottom, "");
-   return lp_build_sub(bld, a_bottom, a_top);
+   LLVMTypeRef i32t = LLVMInt32Type();
+   LLVMValueRef idx_top    = LLVMConstInt(i32t, LP_BLD_QUAD_TOP_LEFT, 0);
+   LLVMValueRef idx_bottom = LLVMConstInt(i32t, LP_BLD_QUAD_BOTTOM_LEFT, 0);
+   LLVMValueRef a_top    = LLVMBuildExtractElement(bld->builder, a, idx_top, "top");
+   LLVMValueRef a_bottom = LLVMBuildExtractElement(bld->builder, a, idx_bottom, "bottom");
+   if (bld->type.floating)
+      return LLVMBuildFSub(bld->builder, a_bottom, a_top, "ddy");
+   else
+      return LLVMBuildSub(bld->builder, a_bottom, a_top, "ddy");
 }