r300: don't reuse destination registers when lowering

Regalloc can sort it out later. No significant change is shader-db, the
one instruction reduction is likely because some optimize pass can
actually work better when we are closer to ssa-like form.

RV530:
total instructions in shared programs: 133718 -> 133717 (<.01%)
instructions in affected programs: 47 -> 46 (-2.13%)
helped: 1
HURT: 0

Signed-off-by: Pavel Ondračka <pavel.ondracka@gmail.com>
Reviewed-by: Filip Gawin <filip@gawin.net>
Tested-by: Filip Gawin <filip@gawin.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/19853>

diff --git a/src/gallium/drivers/r300/compiler/radeon_program_alu.c b/src/gallium/drivers/r300/compiler/radeon_program_alu.c
index 5e32e7b..8e89214 100644 (file)
--- a/src/gallium/drivers/r300/compiler/radeon_program_alu.c
+++ b/src/gallium/drivers/r300/compiler/radeon_program_alu.c
@@ -195,35 +195,10 @@ static struct rc_src_register swizzle_wwww(struct rc_src_register reg)
        return swizzle_smear(reg, RC_SWIZZLE_W);
 }
 
-static int is_dst_safe_to_reuse(struct rc_instruction *inst)
-{
-       const struct rc_opcode_info *info = rc_get_opcode_info(inst->U.I.Opcode);
-       unsigned i;
-
-       assert(info->HasDstReg);
-
-       if (inst->U.I.DstReg.File != RC_FILE_TEMPORARY)
-               return 0;
-
-       for (i = 0; i < info->NumSrcRegs; i++) {
-               if (inst->U.I.SrcReg[i].File == RC_FILE_TEMPORARY &&
-                   inst->U.I.SrcReg[i].Index == inst->U.I.DstReg.Index)
-                       return 0;
-       }
-
-       return 1;
-}
-
-static struct rc_dst_register try_to_reuse_dst(struct radeon_compiler *c,
+static struct rc_dst_register new_dst_reg(struct radeon_compiler *c,
                                               struct rc_instruction *inst)
 {
-       unsigned tmp;
-
-       if (is_dst_safe_to_reuse(inst))
-               tmp = inst->U.I.DstReg.Index;
-       else
-               tmp = rc_find_free_temporary(c);
-
+       unsigned tmp = rc_find_free_temporary(c);
        return dstregtmpmask(tmp, inst->U.I.DstReg.WriteMask);
 }
 
@@ -240,7 +215,7 @@ static void transform_CEIL(struct radeon_compiler* c,
         *     ceil(x) = x+frac(-x)
         */
 
-       struct rc_dst_register dst = try_to_reuse_dst(c, inst);
+       struct rc_dst_register dst = new_dst_reg(c, inst);
        emit1(c, inst->Prev, RC_OPCODE_FRC, NULL, dst, negate(inst->U.I.SrcReg[0]));
        emit2(c, inst->Prev, RC_OPCODE_ADD, &inst->U.I, inst->U.I.DstReg,
                inst->U.I.SrcReg[0], srcreg(RC_FILE_TEMPORARY, dst.Index));
@@ -278,7 +253,7 @@ static void transform_DST(struct radeon_compiler* c,
 static void transform_FLR(struct radeon_compiler* c,
        struct rc_instruction* inst)
 {
-       struct rc_dst_register dst = try_to_reuse_dst(c, inst);
+       struct rc_dst_register dst = new_dst_reg(c, inst);
        emit1(c, inst->Prev, RC_OPCODE_FRC, NULL, dst, inst->U.I.SrcReg[0]);
        emit2(c, inst->Prev, RC_OPCODE_ADD, &inst->U.I, inst->U.I.DstReg,
                inst->U.I.SrcReg[0], negate(srcreg(RC_FILE_TEMPORARY, dst.Index)));
@@ -311,7 +286,7 @@ static void transform_TRUNC(struct radeon_compiler* c,
                abs = srcregswz(RC_FILE_TEMPORARY, tmp, inst->U.I.SrcReg[0].Swizzle);
 
        }
-       struct rc_dst_register dst = try_to_reuse_dst(c, inst);
+       struct rc_dst_register dst = new_dst_reg(c, inst);
        emit1(c, inst->Prev, RC_OPCODE_FRC, NULL, dst, abs);
        emit2(c, inst->Prev, RC_OPCODE_ADD, NULL, dst, abs,
              negate(srcreg(RC_FILE_TEMPORARY, dst.Index)));
@@ -407,7 +382,7 @@ static void transform_LIT(struct radeon_compiler* c,
 static void transform_LRP(struct radeon_compiler* c,
        struct rc_instruction* inst)
 {
-       struct rc_dst_register dst = try_to_reuse_dst(c, inst);
+       struct rc_dst_register dst = new_dst_reg(c, inst);
 
        emit3(c, inst->Prev, RC_OPCODE_MAD, NULL,
                dst,
@@ -422,7 +397,7 @@ static void transform_LRP(struct radeon_compiler* c,
 static void transform_POW(struct radeon_compiler* c,
        struct rc_instruction* inst)
 {
-       struct rc_dst_register tempdst = try_to_reuse_dst(c, inst);
+       struct rc_dst_register tempdst = new_dst_reg(c, inst);
        struct rc_src_register tempsrc = srcreg(RC_FILE_TEMPORARY, tempdst.Index);
        tempdst.WriteMask = RC_MASK_W;
        tempsrc.Swizzle = RC_SWIZZLE_WWWW;
@@ -480,7 +455,7 @@ static void transform_RSQ(struct radeon_compiler* c,
 static void transform_SEQ(struct radeon_compiler* c,
        struct rc_instruction* inst)
 {
-       struct rc_dst_register dst = try_to_reuse_dst(c, inst);
+       struct rc_dst_register dst = new_dst_reg(c, inst);
 
        emit2(c, inst->Prev, RC_OPCODE_ADD, NULL, dst, inst->U.I.SrcReg[0], negate(inst->U.I.SrcReg[1]));
        emit3(c, inst->Prev, RC_OPCODE_CMP, &inst->U.I, inst->U.I.DstReg,
@@ -492,7 +467,7 @@ static void transform_SEQ(struct radeon_compiler* c,
 static void transform_SGE(struct radeon_compiler* c,
        struct rc_instruction* inst)
 {
-       struct rc_dst_register dst = try_to_reuse_dst(c, inst);
+       struct rc_dst_register dst = new_dst_reg(c, inst);
 
        emit2(c, inst->Prev, RC_OPCODE_ADD, NULL, dst, inst->U.I.SrcReg[0], negate(inst->U.I.SrcReg[1]));
        emit3(c, inst->Prev, RC_OPCODE_CMP, &inst->U.I, inst->U.I.DstReg,
@@ -504,7 +479,7 @@ static void transform_SGE(struct radeon_compiler* c,
 static void transform_SGT(struct radeon_compiler* c,
        struct rc_instruction* inst)
 {
-       struct rc_dst_register dst = try_to_reuse_dst(c, inst);
+       struct rc_dst_register dst = new_dst_reg(c, inst);
 
        emit2(c, inst->Prev, RC_OPCODE_ADD, NULL, dst, negate(inst->U.I.SrcReg[0]), inst->U.I.SrcReg[1]);
        emit3(c, inst->Prev, RC_OPCODE_CMP, &inst->U.I, inst->U.I.DstReg,
@@ -516,7 +491,7 @@ static void transform_SGT(struct radeon_compiler* c,
 static void transform_SLE(struct radeon_compiler* c,
        struct rc_instruction* inst)
 {
-       struct rc_dst_register dst = try_to_reuse_dst(c, inst);
+       struct rc_dst_register dst = new_dst_reg(c, inst);
 
        emit2(c, inst->Prev, RC_OPCODE_ADD, NULL, dst, negate(inst->U.I.SrcReg[0]), inst->U.I.SrcReg[1]);
        emit3(c, inst->Prev, RC_OPCODE_CMP, &inst->U.I, inst->U.I.DstReg,
@@ -528,7 +503,7 @@ static void transform_SLE(struct radeon_compiler* c,
 static void transform_SLT(struct radeon_compiler* c,
        struct rc_instruction* inst)
 {
-       struct rc_dst_register dst = try_to_reuse_dst(c, inst);
+       struct rc_dst_register dst = new_dst_reg(c, inst);
 
        emit2(c, inst->Prev, RC_OPCODE_ADD, NULL, dst, inst->U.I.SrcReg[0], negate(inst->U.I.SrcReg[1]));
        emit3(c, inst->Prev, RC_OPCODE_CMP, &inst->U.I, inst->U.I.DstReg,
@@ -540,7 +515,7 @@ static void transform_SLT(struct radeon_compiler* c,
 static void transform_SNE(struct radeon_compiler* c,
        struct rc_instruction* inst)
 {
-       struct rc_dst_register dst = try_to_reuse_dst(c, inst);
+       struct rc_dst_register dst = new_dst_reg(c, inst);
 
        emit2(c, inst->Prev, RC_OPCODE_ADD, NULL, dst, inst->U.I.SrcReg[0], negate(inst->U.I.SrcReg[1]));
        emit3(c, inst->Prev, RC_OPCODE_CMP, &inst->U.I, inst->U.I.DstReg,
@@ -562,7 +537,7 @@ static void transform_SSG(struct radeon_compiler* c,
        unsigned tmp1;
 
        /* 0 < x */
-       dst0 = try_to_reuse_dst(c, inst);
+       dst0 = new_dst_reg(c, inst);
        emit3(c, inst->Prev, RC_OPCODE_CMP, NULL,
              dst0,
              negate(inst->U.I.SrcReg[0]),
@@ -650,7 +625,7 @@ static void transform_r300_vertex_CMP(struct radeon_compiler* c,
         * LRP dst, tmp0, src1, src2
         *
         * Yes, I know, I'm a mad scientist. ~ C. & M. */
-       struct rc_dst_register dst = try_to_reuse_dst(c, inst);
+       struct rc_dst_register dst = new_dst_reg(c, inst);
 
        /* SLT tmp0, src0, 0.0 */
        emit2(c, inst->Prev, RC_OPCODE_SLT, NULL,
@@ -692,7 +667,7 @@ static void transform_r300_vertex_DP3(struct radeon_compiler* c,
 static void transform_r300_vertex_fix_LIT(struct radeon_compiler* c,
        struct rc_instruction* inst)
 {
-       struct rc_dst_register dst = try_to_reuse_dst(c, inst);
+       struct rc_dst_register dst = new_dst_reg(c, inst);
        unsigned constant_swizzle;
        int constant = rc_constants_add_immediate_scalar(&c->Program.Constants,
                                                         0.0000000000000000001,
@@ -718,7 +693,7 @@ static void transform_r300_vertex_SEQ(struct radeon_compiler *c,
 {
        /* x = y  <==>  x >= y && y >= x */
        /* x <= y */
-       struct rc_dst_register dst0 = try_to_reuse_dst(c, inst);
+       struct rc_dst_register dst0 = new_dst_reg(c, inst);
        emit2(c, inst->Prev, RC_OPCODE_SGE, NULL,
              dst0,
              inst->U.I.SrcReg[0],
@@ -745,7 +720,7 @@ static void transform_r300_vertex_SNE(struct radeon_compiler *c,
 {
        /* x != y  <==>  x < y || y < x */
        /* x < y */
-       struct rc_dst_register dst0 = try_to_reuse_dst(c, inst);
+       struct rc_dst_register dst0 = new_dst_reg(c, inst);
        emit2(c, inst->Prev, RC_OPCODE_SLT, NULL,
              dst0,
              inst->U.I.SrcReg[0],
@@ -798,7 +773,7 @@ static void transform_r300_vertex_SSG(struct radeon_compiler* c,
        unsigned tmp1;
 
        /* 0 < x */
-       dst0 = try_to_reuse_dst(c, inst);
+       dst0 = new_dst_reg(c, inst);
        emit2(c, inst->Prev, RC_OPCODE_SLT, NULL,
              dst0,
              builtin_zero,