[PATCH] rs6000: Support UN[GL][ET] in rs6000_maybe_emit_maxc_minc [PR105002]

["Kewen.Lin" <linkw@linux.ibm.com>]

Hi,

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.

Bootstrapped and regtested on powerpc64-linux-gnu P8 and
powerpc64le-linux-gnu P9 and P10.

Is it ok for trunk?

BR,
Kewen
-----
	PR target/105002

gcc/ChangeLog:

	* config/rs6000/rs6000.cc (rs6000_maybe_emit_maxc_minc): Support more
	comparison codes UNLT/UNLE/UNGT/UNGE.

---
 gcc/config/rs6000/rs6000.cc | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 283e8306ff7..b6a2509788f 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -15872,6 +15872,13 @@ rs6000_maybe_emit_maxc_minc (rtx dest, rtx op, rtx true_cond, rtx false_cond)
   if (result_mode != compare_mode)
     return false;

+  /* Canonicalize UN[GL][ET] to [LG][TE].  */
+  if (code == UNGE || code == UNGT || code == UNLE || code == UNLT)
+    {
+      code = reverse_condition_maybe_unordered (code);
+      std::swap (true_cond, false_cond);
+    }
+
   if (code == GE || code == GT)
     max_p = true;
   else if (code == LE || code == LT)
--
2.27.0