gallivm: added lp_build_fract()

src/gallium/auxiliary/gallivm/lp_bld_arit.c

@@ -899,6 +899,19 @@ lp_build_ceil(struct lp_build_context *bld,
 }
 
 
+/**
+ * Return fractional part of 'a' computed as a - floor(f)
+ * Typically used in texture coord arithmetic.
+ */
+LLVMValueRef
+lp_build_fract(struct lp_build_context *bld,
+               LLVMValueRef a)
+{
+   assert(bld->type.floating);
+   return lp_build_sub(bld, a, lp_build_floor(bld, a));
+}
+
+
 /**
  * Convert to integer, through whichever rounding method that's fastest,
  * typically truncating toward zero.

src/gallium/auxiliary/gallivm/lp_bld_arit.h

@@ -148,6 +148,10 @@ LLVMValueRef
 lp_build_trunc(struct lp_build_context *bld,
                LLVMValueRef a);
 
+LLVMValueRef
+lp_build_fract(struct lp_build_context *bld,
+               LLVMValueRef a);
+
 LLVMValueRef
 lp_build_ifloor(struct lp_build_context *bld,
                 LLVMValueRef a);