[gcc r14-310] amdgcn: Fix addsub bug

[gcc r14-310] amdgcn: Fix addsub bug

[Andrew Stubbs]

https://gcc.gnu.org/g:b17c57b06d90f2ca12ea0395046c4ea7d439065f

commit r14-310-gb17c57b06d90f2ca12ea0395046c4ea7d439065f
Author: Andrew Stubbs <ams@codesourcery.com>
Date:   Wed Apr 26 15:23:48 2023 +0100

    amdgcn: Fix addsub bug
    
    The vec_fmsubadd instuction actually had add twice, by mistake.
    
    Also improve code-gen for all the complex patterns by using properly
    undefined values.  Mostly this just prevents the compiler reserving space
    in the stack frame.
    
    gcc/ChangeLog:
    
            * config/gcn/gcn-valu.md (cmul<conj_op><mode>3): Use gcn_gen_undef.
            (cml<addsub_as><mode>4): Likewise.
            (vec_addsub<mode>3): Likewise.
            (cadd<rot><mode>3): Likewise.
            (vec_fmaddsub<mode>4): Likewise.
            (vec_fmsubadd<mode>4): Likewise, and use sub for the odd lanes.

Diff:
---
 gcc/config/gcn/gcn-valu.md | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/gcc/config/gcn/gcn-valu.md b/gcc/config/gcn/gcn-valu.md
index 44c48468dd6..7290cdc2fd0 100644
--- a/gcc/config/gcn/gcn-valu.md
+++ b/gcc/config/gcn/gcn-valu.md
@@ -2323,8 +2323,9 @@
     rtx even = gen_rtx_REG (DImode, EXEC_REG);
     emit_move_insn (even, get_exec (0x5555555555555555UL));
     rtx dest = operands[0];
-    emit_insn (gen_<cmul_subadd><mode>3_exec (dest, t1, t1_perm, dest, even));
-                                                             // a*c-b*d 0
+    emit_insn (gen_<cmul_subadd><mode>3_exec (dest, t1, t1_perm,
+                                              gcn_gen_undef (<MODE>mode),
+                                              even));            // a*c-b*d 0
 
     rtx t2_perm = gen_reg_rtx (<MODE>mode);
     emit_insn (gen_dpp_swap_pairs<mode> (t2_perm, t2));          // b*c a*d
@@ -2368,7 +2369,8 @@
     rtx even = gen_rtx_REG (DImode, EXEC_REG);
     emit_move_insn (even, get_exec (0x5555555555555555UL));
     rtx dest = operands[0];
-    emit_insn (gen_sub<mode>3_exec (dest, t1, t2_perm, dest, even));
+    emit_insn (gen_sub<mode>3_exec (dest, t1, t2_perm,
+                                    gcn_gen_undef (<MODE>mode), even));
 
     rtx odd = gen_rtx_REG (DImode, EXEC_REG);
     emit_move_insn (odd, get_exec (0xaaaaaaaaaaaaaaaaUL));
@@ -2392,7 +2394,8 @@
     rtx dest = operands[0];
     rtx x = operands[1];
     rtx y = operands[2];
-    emit_insn (gen_sub<mode>3_exec (dest, x, y, dest, even));
+    emit_insn (gen_sub<mode>3_exec (dest, x, y, gcn_gen_undef (<MODE>mode),
+                                    even));
     rtx odd = gen_rtx_REG (DImode, EXEC_REG);
     emit_move_insn (odd, get_exec (0xaaaaaaaaaaaaaaaaUL));
     emit_insn (gen_add<mode>3_exec (dest, x, y, dest, odd));
@@ -2419,7 +2422,9 @@
 
     rtx even = gen_rtx_REG (DImode, EXEC_REG);
     emit_move_insn (even, get_exec (0x5555555555555555UL));
-    emit_insn (gen_<cadd_subadd><mode>3_exec (dest, x, y, dest, even));
+    emit_insn (gen_<cadd_subadd><mode>3_exec (dest, x, y,
+                                              gcn_gen_undef (<MODE>mode),
+                                              even));
     rtx odd = gen_rtx_REG (DImode, EXEC_REG);
     emit_move_insn (odd, get_exec (0xaaaaaaaaaaaaaaaaUL));
     emit_insn (gen_<cadd_addsub><mode>3_exec (dest, x, y, dest, odd));
@@ -2439,7 +2444,8 @@
     rtx even = gen_rtx_REG (DImode, EXEC_REG);
     emit_move_insn (even, get_exec (0x5555555555555555UL));
     rtx dest = operands[0];
-    emit_insn (gen_sub<mode>3_exec (dest, t1, operands[3], dest, even));
+    emit_insn (gen_sub<mode>3_exec (dest, t1, operands[3],
+                                    gcn_gen_undef (<MODE>mode), even));
     rtx odd = gen_rtx_REG (DImode, EXEC_REG);
     emit_move_insn (odd, get_exec (0xaaaaaaaaaaaaaaaaUL));
     emit_insn (gen_add<mode>3_exec (dest, t1, operands[3], dest, odd));
@@ -2459,10 +2465,11 @@
     rtx even = gen_rtx_REG (DImode, EXEC_REG);
     emit_move_insn (even, get_exec (0x5555555555555555UL));
     rtx dest = operands[0];
-    emit_insn (gen_add<mode>3_exec (dest, t1, operands[3], dest, even));
+    emit_insn (gen_add<mode>3_exec (dest, t1, operands[3],
+                                    gcn_gen_undef (<MODE>mode), even));
     rtx odd = gen_rtx_REG (DImode, EXEC_REG);
     emit_move_insn (odd, get_exec (0xaaaaaaaaaaaaaaaaUL));
-    emit_insn (gen_add<mode>3_exec (dest, t1, operands[3], dest, odd));
+    emit_insn (gen_sub<mode>3_exec (dest, t1, operands[3], dest, odd));
 
     DONE;
   })