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From: "luoxhu at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/102239] powerpc suboptimal boolean test of contiguous bits
Date: Fri, 26 Nov 2021 08:50:48 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D102239

--- Comment #4 from luoxhu at gcc dot gnu.org ---
Simply adjust the sequence of dot instruction could produce expected code, =
is
this correct?


foo:
.LFB0:
        .cfi_startproc
        rldicr. 3,3,29,1
        beq 0,.L2
#APP
 # 10 "pr102239.c" 1
        # if
 # 0 "" 2
#NO_APP
        blr
        .p2align 4,,15
.L2:
#APP
 # 12 "pr102239.c" 1
        # else
 # 0 "" 2
#NO_APP
        blr



 git diff
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index c9ce0550df1..2f0b5992bbf 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -11749,9 +11749,9 @@ rs6000_emit_2insn_and (machine_mode mode, rtx
*operands, bool expand, int dot)
        {
          rtx tmp =3D gen_rtx_ASHIFT (mode, operands[1], GEN_INT (shift));
          tmp =3D gen_rtx_AND (mode, tmp, GEN_INT (val << shift));
-         emit_move_insn (operands[0], tmp);
-         tmp =3D gen_rtx_LSHIFTRT (mode, operands[0], GEN_INT (shift));
          rs6000_emit_dot_insn (operands[0], tmp, dot, dot ? operands[3] : =
0);
+         tmp =3D gen_rtx_LSHIFTRT (mode, operands[0], GEN_INT (shift));
+         emit_move_insn (operands[0], tmp);
        }
       return;
     }=