Mesa (master): i965: Use greater-equal cmod to implement maximum.

[Matt Turner]

Module: Mesa
Branch: master
Commit: 3b7f683f3bbbd93e417a6f42ec7c609465be49de
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=3b7f683f3bbbd93e417a6f42ec7c609465be49de

Author: Matt Turner <mattst88 at gmail.com>
Date:   Mon Feb  9 21:11:46 2015 -0800

i965: Use greater-equal cmod to implement maximum.

The docs specifically call out SEL with .l and .ge as the
implementations of MIN and MAX respectively. Among other things, SEL
with these conditional mods are commutative.

Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>

---

 src/mesa/drivers/dri/i965/brw_fs_visitor.cpp      |    5 ++++-
 src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp    |    6 +++---
 src/mesa/drivers/dri/i965/brw_vec4_vp.cpp         |    4 ++--
 src/mesa/drivers/dri/i965/brw_vec4_vs_visitor.cpp |    2 +-
 4 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
index 7486071..4b48f2d 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
@@ -321,6 +321,9 @@ void
 fs_visitor::emit_minmax(enum brw_conditional_mod conditionalmod, const fs_reg &dst,
                         const fs_reg &src0, const fs_reg &src1)
 {
+   assert(conditionalmod == BRW_CONDITIONAL_GE ||
+          conditionalmod == BRW_CONDITIONAL_L);
+
    fs_inst *inst;
 
    if (brw->gen >= 6) {
@@ -1956,7 +1959,7 @@ fs_visitor::rescale_texcoord(fs_reg coordinate, int coord_components,
 	    chan = offset(chan, i);
 
 	    inst = emit(BRW_OPCODE_SEL, chan, chan, fs_reg(0.0f));
-	    inst->conditional_mod = BRW_CONDITIONAL_G;
+	    inst->conditional_mod = BRW_CONDITIONAL_GE;
 
 	    /* Our parameter comes in as 1.0/width or 1.0/height,
 	     * because that's what people normally want for doing
diff --git a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
index 6154e43..be071d7 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
@@ -517,7 +517,7 @@ vec4_visitor::emit_unpack_snorm_4x8(const dst_reg &dst, src_reg src0)
    emit(MUL(scaled, src_reg(f), src_reg(1.0f / 127.0f)));
 
    dst_reg max(this, glsl_type::vec4_type);
-   emit_minmax(BRW_CONDITIONAL_G, max, src_reg(scaled), src_reg(-1.0f));
+   emit_minmax(BRW_CONDITIONAL_GE, max, src_reg(scaled), src_reg(-1.0f));
    emit_minmax(BRW_CONDITIONAL_L, dst, src_reg(max), src_reg(1.0f));
 }
 
@@ -545,7 +545,7 @@ void
 vec4_visitor::emit_pack_snorm_4x8(const dst_reg &dst, const src_reg &src0)
 {
    dst_reg max(this, glsl_type::vec4_type);
-   emit_minmax(BRW_CONDITIONAL_G, max, src0, src_reg(-1.0f));
+   emit_minmax(BRW_CONDITIONAL_GE, max, src0, src_reg(-1.0f));
 
    dst_reg min(this, glsl_type::vec4_type);
    emit_minmax(BRW_CONDITIONAL_L, min, src_reg(max), src_reg(1.0f));
@@ -1683,7 +1683,7 @@ vec4_visitor::visit(ir_expression *ir)
       emit_minmax(BRW_CONDITIONAL_L, result_dst, op[0], op[1]);
       break;
    case ir_binop_max:
-      emit_minmax(BRW_CONDITIONAL_G, result_dst, op[0], op[1]);
+      emit_minmax(BRW_CONDITIONAL_GE, result_dst, op[0], op[1]);
       break;
 
    case ir_binop_pow:
diff --git a/src/mesa/drivers/dri/i965/brw_vec4_vp.cpp b/src/mesa/drivers/dri/i965/brw_vec4_vp.cpp
index a5a5e7b..ba3264d 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_vp.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_vp.cpp
@@ -226,7 +226,7 @@ vec4_vs_visitor::emit_program_code()
                /* if (tmp.y < 0) tmp.y = 0; */
                src_reg tmp_y = swizzle(src[0], BRW_SWIZZLE_YYYY);
                result.writemask = WRITEMASK_Z;
-               emit_minmax(BRW_CONDITIONAL_G, result, tmp_y, src_reg(0.0f));
+               emit_minmax(BRW_CONDITIONAL_GE, result, tmp_y, src_reg(0.0f));
 
                src_reg clamped_y(result);
                clamped_y.swizzle = BRW_SWIZZLE_ZZZZ;
@@ -313,7 +313,7 @@ vec4_vs_visitor::emit_program_code()
       }
 
       case OPCODE_MAX:
-         emit_minmax(BRW_CONDITIONAL_G, dst, src[0], src[1]);
+         emit_minmax(BRW_CONDITIONAL_GE, dst, src[0], src[1]);
          break;
 
       case OPCODE_MIN:
diff --git a/src/mesa/drivers/dri/i965/brw_vec4_vs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_vec4_vs_visitor.cpp
index 129c2db..4baf73e 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_vs_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_vs_visitor.cpp
@@ -97,7 +97,7 @@ vec4_vs_visitor::emit_prolog()
                dst.type = brw_type_for_base_type(glsl_type::vec4_type);
                emit(MOV(dst, src_reg(reg_d)));
                emit(MUL(dst, src_reg(dst), src_reg(es3_normalize_factor)));
-               emit_minmax(BRW_CONDITIONAL_G, dst, src_reg(dst), src_reg(-1.0f));
+               emit_minmax(BRW_CONDITIONAL_GE, dst, src_reg(dst), src_reg(-1.0f));
             } else {
                /* The following equations are from the OpenGL 3.2 specification:
                 *