[PATCH v2] rs6000: suboptimal code for returning bool value on target ppc

[Ajit Agarwal via Gcc-patches]

Hello All:

This patch eliminates unncessary zero extension with ree pass.
Bootstrapped and regtested on powerpc64-linux-gnu.

Thanks & Regards
Ajit

        rs6000: suboptimal code for returning bool value on 
        target ppc.

        Eliminate unnecessary redundantzero extension.

        2023-03-19  Ajit Kumar Agarwal  <aagar...@linux.ibm.com>

gcc/ChangeLog:

        * ree.cc: Add support of AND opcode to eliminate unnecessary
        zero extension.
---
 gcc/ree.cc | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/gcc/ree.cc b/gcc/ree.cc
index 413aec7c8eb..d09f55149b1 100644
--- a/gcc/ree.cc
+++ b/gcc/ree.cc
@@ -319,7 +319,7 @@ combine_set_extension (ext_cand *cand, rtx_insn *curr_insn, 
rtx *orig_set)
 {
   rtx orig_src = SET_SRC (*orig_set);
   machine_mode orig_mode = GET_MODE (SET_DEST (*orig_set));
-  rtx new_set;
+  rtx new_set = NULL_RTX;
   rtx cand_pat = single_set (cand->insn);
 
   /* If the extension's source/destination registers are not the same
@@ -370,7 +370,7 @@ combine_set_extension (ext_cand *cand, rtx_insn *curr_insn, 
rtx *orig_set)
     {
       /* Only IF_THEN_ELSE of phi-type copies are combined.  Otherwise,
          in general, IF_THEN_ELSE should not be combined.  */
-      return false;
+      return true;
     }
   else
     {
@@ -713,12 +713,15 @@ merge_def_and_ext (ext_cand *cand, rtx_insn *def_insn, 
ext_state *state)
   if (sub_rtx == NULL)
     return false;
 
-  if (GET_MODE (SET_DEST (*sub_rtx)) == ext_src_mode
+  bool copy_needed
+    = (REGNO (SET_DEST (cand->expr)) != REGNO (XEXP (SET_SRC (cand->expr), 
0)));
+
+  if (!copy_needed || (GET_MODE (SET_DEST (*sub_rtx)) == ext_src_mode
          || ((state->modified[INSN_UID (def_insn)].kind
-              == (cand->code == ZERO_EXTEND
+              == (cand->code == ZERO_EXTEND || cand->code == AND
                   ? EXT_MODIFIED_ZEXT : EXT_MODIFIED_SEXT))
              && state->modified[INSN_UID (def_insn)].mode
-                == ext_src_mode))
+                == ext_src_mode)))
     {
       if (GET_MODE_UNIT_SIZE (GET_MODE (SET_DEST (*sub_rtx)))
          >= GET_MODE_UNIT_SIZE (cand->mode))
@@ -744,7 +747,8 @@ merge_def_and_ext (ext_cand *cand, rtx_insn *def_insn, 
ext_state *state)
 static inline rtx
 get_extended_src_reg (rtx src)
 {
-  while (GET_CODE (src) == SIGN_EXTEND || GET_CODE (src) == ZERO_EXTEND)
+  while (GET_CODE (src) == SIGN_EXTEND || GET_CODE (src) == ZERO_EXTEND
+       || GET_CODE (src) == AND)
     src = XEXP (src, 0);
   gcc_assert (REG_P (src));
   return src;
@@ -993,7 +997,7 @@ combine_reaching_defs (ext_cand *cand, const_rtx set_pat, 
ext_state *state)
       machine_mode mode;
 
       if (state->modified[INSN_UID (cand->insn)].kind
-         != (cand->code == ZERO_EXTEND
+         != (cand->code == ZERO_EXTEND || cand->code == AND
              ? EXT_MODIFIED_ZEXT : EXT_MODIFIED_SEXT)
          || state->modified[INSN_UID (cand->insn)].mode != cand->mode
          || (set == NULL_RTX))
@@ -1052,7 +1056,7 @@ combine_reaching_defs (ext_cand *cand, const_rtx set_pat, 
ext_state *state)
            {
              ext_modified *modified = &state->modified[INSN_UID (def_insn)];
              if (modified->kind == EXT_MODIFIED_NONE)
-               modified->kind = (cand->code == ZERO_EXTEND ? EXT_MODIFIED_ZEXT
+               modified->kind = (cand->code == ZERO_EXTEND || cand->code == 
AND  ? EXT_MODIFIED_ZEXT
                                                            : 
EXT_MODIFIED_SEXT);
 
              if (copy_needed)
@@ -1106,7 +1110,7 @@ add_removable_extension (const_rtx expr, rtx_insn *insn,
   mode = GET_MODE (dest);
 
   if (REG_P (dest)
-      && (code == SIGN_EXTEND || code == ZERO_EXTEND)
+      && (code == SIGN_EXTEND || code == ZERO_EXTEND || code == AND)
       && REG_P (XEXP (src, 0)))
     {
       rtx reg = XEXP (src, 0);
-- 
2.31.1