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| author | Segher Boessenkool <segher@kernel.crashing.org> | 2017-11-28 01:17:16 +0100 |
|---|---|---|
| committer | Segher Boessenkool <segher@gcc.gnu.org> | 2017-11-28 01:17:16 +0100 |
| commit | fd8bf76c908297f96f240954c43732579bb95105 (patch) | |
| tree | 3139451e525e77a0975c2114c48e110f3722dd21 | |
| parent | 2ac1a8d832dbaad726cc5f787646ff20c9b05aeb (diff) | |
| download | gcc-fd8bf76c908297f96f240954c43732579bb95105.zip gcc-fd8bf76c908297f96f240954c43732579bb95105.tar.gz gcc-fd8bf76c908297f96f240954c43732579bb95105.tar.bz2 | |
rs6000: Improve scc isel
If we have a negative condition we can use a literal 0 in the isel,
instead of having to load it into a register. If the condition is from
a comparison with an immediate we can change e.g. LT to LE and adjust
the immediate, saving a li instruction.
* config/rs6000/rs6000.md (<code><GPR:mode><GPR2:mode>2_isel): Change
LT/GT/LTU/GTU to LE/GE/LEU/GEU where possible.
From-SVN: r255186
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/config/rs6000/rs6000.md | 36 |
2 files changed, 37 insertions, 4 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 10d5634..d3b2f5b 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2017-11-27 Segher Boessenkool <segher@kernel.crashing.org> + + * config/rs6000/rs6000.md (<code><GPR:mode><GPR2:mode>2_isel): Change + LT/GT/LTU/GTU to LE/GE/LEU/GEU where possible. + 2017-11-27 Michael Meissner <meissner@linux.vnet.ibm.com> PR middle_end/82333 diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md index 276ad8a..c9b35c9 100644 --- a/gcc/config/rs6000/rs6000.md +++ b/gcc/config/rs6000/rs6000.md @@ -12333,8 +12333,34 @@ "&& 1" [(pc)] { - if (<CODE> == NE || <CODE> == LE || <CODE> == GE - || <CODE> == LEU || <CODE> == GEU) + rtx_code code = <CODE>; + if (CONST_INT_P (operands[2]) && code != EQ && code != NE) + { + HOST_WIDE_INT val = INTVAL (operands[2]); + if (code == LT && val != -0x8000) + { + code = LE; + val--; + } + if (code == GT && val != 0x7fff) + { + code = GE; + val++; + } + if (code == LTU && val != 0) + { + code = LEU; + val--; + } + if (code == GTU && val != 0xffff) + { + code = GEU; + val++; + } + operands[2] = GEN_INT (val); + } + + if (code == NE || code == LE || code == GE || code == LEU || code == GEU) operands[3] = const0_rtx; else { @@ -12353,14 +12379,16 @@ rtx c1 = gen_rtx_COMPARE (<UNS>mode, operands[1], operands[2]); emit_insn (gen_rtx_SET (operands[5], c1)); - rtx c2 = gen_rtx_fmt_ee (<CODE>, <GPR:MODE>mode, operands[5], const0_rtx); + rtx c2 = gen_rtx_fmt_ee (code, <GPR:MODE>mode, operands[5], const0_rtx); rtx x = gen_rtx_IF_THEN_ELSE (<GPR:MODE>mode, c2, operands[4], operands[3]); emit_move_insn (operands[0], x); DONE; } [(set (attr "cost") - (if_then_else (match_test "<CODE> == NE || <CODE> == LE || <CODE> == GE + (if_then_else (match_test "(CONST_INT_P (operands[2]) && <CODE> != EQ) + || <CODE> == NE + || <CODE> == LE || <CODE> == GE || <CODE> == LEU || <CODE> == GEU") (const_string "9") (const_string "10")))]) |