[gcc(refs/users/meissner/heads/work078)] Don't do int cmoves for IEEE comparisons.

[Michael Meissner <meissner@gcc.gnu.org>]

https://gcc.gnu.org/g:7f7055147cfde9158d33f790bba8cb85cc8b7581

commit 7f7055147cfde9158d33f790bba8cb85cc8b7581
Author: Michael Meissner <meissner@linux.ibm.com>
Date:   Thu Feb 17 00:53:38 2022 -0500

    Don't do int cmoves for IEEE comparisons.
    
    Protect int cmove from raising an assertion if it is trying to do an int
    conditional move where the test involves IEEE comparisons that must be
    done with a CCFPmode instead of the CCmode normally used for int cmoves.
    
    2022-02-17  Michael Meissner  <meissner@the-meissners.org>
    
    gcc/
            PR target/104256
            * config/rs6000/rs6000.cc (rs6000_emit_int_cmove): Don't do
            integer conditional moves if the test involves IEEE comparisons.
    
    gcc/testsuite/
            PR target/104256
            * gcc.target/powerpc/ppc-fortran/pr104254.f90: New test.

Diff:
---
 gcc/config/rs6000/rs6000.cc                        |  9 ++++++++
 .../gcc.target/powerpc/ppc-fortran/pr104254.f90    | 25 ++++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index f56cf66313a..10af34fca69 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -16181,6 +16181,15 @@ rs6000_emit_int_cmove (rtx dest, rtx op, rtx true_cond, rtx false_cond)
   if (mode != SImode && (!TARGET_POWERPC64 || mode != DImode))
     return false;
 
+  /* Don't do int cmoves for IEEE comparisons.  The rs6000_generate_compare
+     function will eventually raise an exception because the mode used is
+     CCmode (due to this being an int cmove), but you can only do these
+     comparsions with CCFP mode.  */
+  enum rtx_code op_code = GET_CODE (op);
+  if (op_code == ORDERED || op_code == UNORDERED || op_code == UNEQ || op_code == LTGT
+      || op_code == UNGT || op_code == UNLT || op_code == UNGE || op_code == UNLE)
+    return false;
+					
   /* We still have to do the compare, because isel doesn't do a
      compare, it just looks at the CRx bits set by a previous compare
      instruction.  */
diff --git a/gcc/testsuite/gcc.target/powerpc/ppc-fortran/pr104254.f90 b/gcc/testsuite/gcc.target/powerpc/ppc-fortran/pr104254.f90
new file mode 100644
index 00000000000..d1bfab23482
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/ppc-fortran/pr104254.f90
@@ -0,0 +1,25 @@
+! { dg-do compile }
+! { dg-require-effective-target powerpc_p9vector_ok }
+! { dg-options "-mdejagnu-cpu=power9 -O1 -fnon-call-exceptions" }
+
+! PR target/104254.  GCC would raise an assertion error if this program was
+! compiled with -O1 and -fnon-call-exceptions on a power9 or higher.  The issue
+! occurs because at this optimization level, the compiler is trying to make
+! a conditional move to store integers using a 32-bit floating point compare.
+! It wants to use UNLE, which is not supported for integer modes.
+  
+  real :: a(2), nan
+  real, allocatable :: c(:)
+  integer :: ia(1)
+
+  nan = 0.0
+  nan = 0.0/nan
+
+  a(:) = nan
+  ia = maxloc (a)
+  if (ia(1).ne.1) STOP 1
+
+  allocate (c(1))
+  c(:) = nan
+  deallocate (c)
+end