[Mesa-dev] [PATCH] gallivm: fix [IU]MUL_HI regression harder

[Nicolai Hähnle]

From: Nicolai Hähnle <nicolai.haehnle at amd.com>

The fix in commit 88f791db75e9f065bac8134e0937e1b76600aa36 was insufficient
for radeonsi because the vector case was not handled properly. It seems
piglit only covers the scalar case, unfortunately.

Fixes GL45-CTS.shader_bitfield_operation.[iu]mulExtended.*
---
 src/gallium/auxiliary/gallivm/lp_bld_arit.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/src/gallium/auxiliary/gallivm/lp_bld_arit.c b/src/gallium/auxiliary/gallivm/lp_bld_arit.c
index 43ad238..5553cb1 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_arit.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_arit.c
@@ -1230,42 +1230,46 @@ lp_build_mul_32_lohi_cpu(struct lp_build_context *bld,
  * Emits generic code.
  */
 LLVMValueRef
 lp_build_mul_32_lohi(struct lp_build_context *bld,
                      LLVMValueRef a,
                      LLVMValueRef b,
                      LLVMValueRef *res_hi)
 {
    struct gallivm_state *gallivm = bld->gallivm;
    LLVMBuilderRef builder = gallivm->builder;
-   LLVMValueRef tmp;
+   LLVMValueRef tmp, shift, res_lo;
    struct lp_type type_tmp;
-   LLVMTypeRef wide_type, cast_type;
+   LLVMTypeRef wide_type, narrow_type;
 
    type_tmp = bld->type;
+   narrow_type = lp_build_vec_type(gallivm, type_tmp);
    type_tmp.width *= 2;
    wide_type = lp_build_vec_type(gallivm, type_tmp);
-   type_tmp = bld->type;
-   type_tmp.length *= 2;
-   cast_type = lp_build_vec_type(gallivm, type_tmp);
+   shift = lp_build_const_vec(gallivm, type_tmp, 32);
 
    if (bld->type.sign) {
       a = LLVMBuildSExt(builder, a, wide_type, "");
       b = LLVMBuildSExt(builder, b, wide_type, "");
    } else {
       a = LLVMBuildZExt(builder, a, wide_type, "");
       b = LLVMBuildZExt(builder, b, wide_type, "");
    }
    tmp = LLVMBuildMul(builder, a, b, "");
-   tmp = LLVMBuildBitCast(builder, tmp, cast_type, "");
-   *res_hi = lp_build_uninterleave1(gallivm, bld->type.length * 2, tmp, 1);
-   return lp_build_uninterleave1(gallivm, bld->type.length * 2, tmp, 0);
+
+   res_lo = LLVMBuildTrunc(builder, tmp, narrow_type, "");
+
+   /* Since we truncate anyway, LShr and AShr are equivalent. */
+   tmp = LLVMBuildLShr(builder, tmp, shift, "");
+   *res_hi = LLVMBuildTrunc(builder, tmp, narrow_type, "");
+
+   return res_lo;
 }
 
 
 /* a * b + c */
 LLVMValueRef
 lp_build_mad(struct lp_build_context *bld,
              LLVMValueRef a,
              LLVMValueRef b,
              LLVMValueRef c)
 {
-- 
2.7.4