diff options
| author | Kewen Lin <linkw@linux.ibm.com> | 2022-04-05 22:18:30 -0500 |
|---|---|---|
| committer | Kewen Lin <linkw@linux.ibm.com> | 2022-04-05 22:18:30 -0500 |
| commit | 83b43c74bbbdc6b6903350b220b932c6f774bdfd (patch) | |
| tree | f52493d6832c2513e0e32d760107fe610e548bdd /gcc | |
| parent | 9d84ed6812dce4a50e64334e7cc4abdeebe41523 (diff) | |
| download | gcc-83b43c74bbbdc6b6903350b220b932c6f774bdfd.zip gcc-83b43c74bbbdc6b6903350b220b932c6f774bdfd.tar.gz gcc-83b43c74bbbdc6b6903350b220b932c6f774bdfd.tar.bz2 | |
rs6000: Support UN[GL][ET] in rs6000_maybe_emit_maxc_minc [PR105002]
Commit r12-7687 exposed one miss optimization chance in function
rs6000_maybe_emit_maxc_minc, for now it only considers comparison
codes GE/GT/LE/LT, but it can support more variants with codes
UNLT/UNLE/UNGT/UNGE by reversing them into the equivalent ones
with GE/GT/LE/LT.
gcc/ChangeLog:
PR target/105002
* config/rs6000/rs6000.cc (rs6000_maybe_emit_maxc_minc): Support more
comparison codes UNLT/UNLE/UNGT/UNGE.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/config/rs6000/rs6000.cc | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc index cb18db0..ceaddaf 100644 --- a/gcc/config/rs6000/rs6000.cc +++ b/gcc/config/rs6000/rs6000.cc @@ -15867,11 +15867,30 @@ rs6000_maybe_emit_maxc_minc (rtx dest, rtx op, rtx true_cond, rtx false_cond) rtx op1 = XEXP (op, 1); machine_mode compare_mode = GET_MODE (op0); machine_mode result_mode = GET_MODE (dest); - bool max_p = false; if (result_mode != compare_mode) return false; + /* See the comments of this function, it simply expects GE/GT/LE/LT in + the checks, but for the reversible equivalent UNLT/UNLE/UNGT/UNGE, + we need to do the reversions first to make the following checks + support fewer cases, like: + + (a UNLT b) ? op1 : op2 => (a >= b) ? op2 : op1; + (a UNLE b) ? op1 : op2 => (a > b) ? op2 : op1; + (a UNGT b) ? op1 : op2 => (a <= b) ? op2 : op1; + (a UNGE b) ? op1 : op2 => (a < b) ? op2 : op1; + + By the way, if we see these UNLT/UNLE/UNGT/UNGE it's guaranteed + that we have 4-way condition codes (LT/GT/EQ/UN), so we do not + have to check for fast-math or the like. */ + if (code == UNGE || code == UNGT || code == UNLE || code == UNLT) + { + code = reverse_condition_maybe_unordered (code); + std::swap (true_cond, false_cond); + } + + bool max_p; if (code == GE || code == GT) max_p = true; else if (code == LE || code == LT) |