[Mesa-dev] [PATCH] llvmpipe: use vpkswss when dst is signed

[Oded Gabbay]

This patch fixes a bug when building a pack instruction.

For POWER (altivec), in case the destination is signed and the
src width is 32, we need to use vpkswss. The original code used vpkuwus,
which emits an unsigned result.

This fixes the following piglit tests on ppc64le:
- spec at arb_color_buffer_float@gl_rgba8-drawpixels
- shaders at glsl-fs-fogscale
- spec at arb_timer_query@query gl_timestamp

I've also corrected some coding style issues in the function.

Signed-off-by: Oded Gabbay <oded.gabbay at gmail.com>
---
 src/gallium/auxiliary/gallivm/lp_bld_pack.c | 44 ++++++++++++++++-------------
 1 file changed, 25 insertions(+), 19 deletions(-)

diff --git a/src/gallium/auxiliary/gallivm/lp_bld_pack.c b/src/gallium/auxiliary/gallivm/lp_bld_pack.c
index cdf6d80..39a5c3a 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_pack.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_pack.c
@@ -461,15 +461,15 @@ lp_build_pack2(struct gallivm_state *gallivm,
    assert(src_type.length * 2 == dst_type.length);
 
    /* Check for special cases first */
-   if((util_cpu_caps.has_sse2 || util_cpu_caps.has_altivec) &&
-       src_type.width * src_type.length >= 128) {
+   if ((util_cpu_caps.has_sse2 || util_cpu_caps.has_altivec) &&
+        src_type.width * src_type.length >= 128) {
       const char *intrinsic = NULL;
       boolean swap_intrinsic_operands = FALSE;
 
       switch(src_type.width) {
       case 32:
          if (util_cpu_caps.has_sse2) {
-           if(dst_type.sign) {
+           if (dst_type.sign) {
               intrinsic = "llvm.x86.sse2.packssdw.128";
            }
            else {
@@ -477,34 +477,39 @@ lp_build_pack2(struct gallivm_state *gallivm,
                  intrinsic = "llvm.x86.sse41.packusdw";
               }
            }
-         } else if (util_cpu_caps.has_altivec) {
+         }
+         else if (util_cpu_caps.has_altivec) {
             if (dst_type.sign) {
-              intrinsic = "llvm.ppc.altivec.vpkswus";
-           } else {
-              intrinsic = "llvm.ppc.altivec.vpkuwus";
-           }
+               intrinsic = "llvm.ppc.altivec.vpkswss";
+            }
+            else {
+               intrinsic = "llvm.ppc.altivec.vpkuwus";
+            }
 #ifdef PIPE_ARCH_LITTLE_ENDIAN
-           swap_intrinsic_operands = TRUE;
+            swap_intrinsic_operands = TRUE;
 #endif
          }
          break;
       case 16:
          if (dst_type.sign) {
             if (util_cpu_caps.has_sse2) {
-              intrinsic = "llvm.x86.sse2.packsswb.128";
-            } else if (util_cpu_caps.has_altivec) {
-              intrinsic = "llvm.ppc.altivec.vpkshss";
+               intrinsic = "llvm.x86.sse2.packsswb.128";
+            }
+            else if (util_cpu_caps.has_altivec) {
+               intrinsic = "llvm.ppc.altivec.vpkshss";
 #ifdef PIPE_ARCH_LITTLE_ENDIAN
-              swap_intrinsic_operands = TRUE;
+               swap_intrinsic_operands = TRUE;
 #endif
             }
-         } else {
+         }
+         else {
             if (util_cpu_caps.has_sse2) {
-              intrinsic = "llvm.x86.sse2.packuswb.128";
-            } else if (util_cpu_caps.has_altivec) {
-	      intrinsic = "llvm.ppc.altivec.vpkshus";
+               intrinsic = "llvm.x86.sse2.packuswb.128";
+            }
+            else if (util_cpu_caps.has_altivec) {
+               intrinsic = "llvm.ppc.altivec.vpkshus";
 #ifdef PIPE_ARCH_LITTLE_ENDIAN
-              swap_intrinsic_operands = TRUE;
+               swap_intrinsic_operands = TRUE;
 #endif
             }
          }
@@ -516,7 +521,8 @@ lp_build_pack2(struct gallivm_state *gallivm,
             LLVMTypeRef intr_vec_type = lp_build_vec_type(gallivm, intr_type);
             if (swap_intrinsic_operands) {
                res = lp_build_intrinsic_binary(builder, intrinsic, intr_vec_type, hi, lo);
-            } else {
+            }
+            else {
                res = lp_build_intrinsic_binary(builder, intrinsic, intr_vec_type, lo, hi);
             }
             if (dst_vec_type != intr_vec_type) {
-- 
2.5.0