[gcc r15-5304] rs6000: Rework vector integer comparison in rs6000_emit_vector_compare - p2

[Kewen Lin via Gcc-cvs]

https://gcc.gnu.org/g:d35ee820b43e80a1298deecc60fdee32d9416eff

commit r15-5304-gd35ee820b43e80a1298deecc60fdee32d9416eff
Author: Kewen Lin <li...@linux.ibm.com>
Date:   Fri Nov 15 03:46:33 2024 +0000

    rs6000: Rework vector integer comparison in rs6000_emit_vector_compare - p2
    
    The current handlings in rs6000_emit_vector_compare is a bit
    complicated to me, especially after we emit vector float
    comparison insn with the given code directly.  So it's better
    to refactor the handlings of vector integer comparison here.
    
    This is part 2, it's to refactor the handlings on LT and LTU.
    This patch doesn't introduce any functionality change.
    
    gcc/ChangeLog:
    
            * config/rs6000/rs6000.cc (rs6000_emit_vector_compare): Refine the
            handlings for operators LT and LTU.

Diff:
---
 gcc/config/rs6000/rs6000.cc | 32 +++++++++-----------------------
 1 file changed, 9 insertions(+), 23 deletions(-)

diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 44477657bc29..718d65951e7f 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -16042,22 +16042,18 @@ rs6000_emit_vector_compare (enum rtx_code rcode,
       emit_insn (gen_rtx_SET (mask, gen_rtx_fmt_ee (rcode, dmode, op0, op1)));
       return mask;
     }
-
-  bool swap_operands = false;
-  bool try_again = false;
+  else if (rcode == LT || rcode == LTU)
+    {
+      /* lt{,u}(a,b) = gt{,u}(b,a)  */
+      enum rtx_code code = swap_condition (rcode);
+      std::swap (op0, op1);
+      mask = gen_reg_rtx (dmode);
+      emit_insn (gen_rtx_SET (mask, gen_rtx_fmt_ee (code, dmode, op0, op1)));
+      return mask;
+    }
 
   switch (rcode)
     {
-    case LT:
-      rcode = GT;
-      swap_operands = true;
-      try_again = true;
-      break;
-    case LTU:
-      rcode = GTU;
-      swap_operands = true;
-      try_again = true;
-      break;
     case NE:
       /* Invert condition and try again.
         e.g., A != B becomes ~(A==B).  */
@@ -16131,16 +16127,6 @@ rs6000_emit_vector_compare (enum rtx_code rcode,
       return NULL_RTX;
     }
 
-  if (try_again)
-    {
-      if (swap_operands)
-       std::swap (op0, op1);
-
-      mask = rs6000_emit_vector_compare (rcode, op0, op1, dmode);
-      if (mask)
-       return mask;
-    }
-
   /* You only get two chances.  */
   return NULL_RTX;
 }