[gcc r15-702] rs6000: Fix ICE on IEEE128 long double without vsx [PR114402]

[Kewen Lin via Gcc-cvs]

https://gcc.gnu.org/g:c547e353597ac4e0af09c2faca8c5a16744dcea4

commit r15-702-gc547e353597ac4e0af09c2faca8c5a16744dcea4
Author: Kewen Lin <li...@linux.ibm.com>
Date:   Mon May 20 21:01:06 2024 -0500

    rs6000: Fix ICE on IEEE128 long double without vsx [PR114402]
    
    As PR114402 shows, we supports IEEE128 format long double
    even if there is no vsx support, but there is an ICE about
    cbranch as the test case shows.  For now, we only supports
    compare:CCFP pattern for IEEE128 fp if TARGET_FLOAT128_HW,
    so in function rs6000_generate_compare we have a check with
    !TARGET_FLOAT128_HW && FLOAT128_VECTOR_P (mode) to make
    !TARGET_FLOAT128_HW IEEE128 fp handling go with libcall.
    But unfortunately the IEEE128 without vsx support doesn't
    meet FLOAT128_VECTOR_P (mode) so it goes further with an
    unmatched compare:CCFP pattern which triggers ICE.
    
    So this patch is to make rs6000_generate_compare consider
    IEEE128 without vsx as well then it can end up with libcall.
    
            PR target/114402
    
    gcc/ChangeLog:
    
            * config/rs6000/rs6000.cc (rs6000_generate_compare): Make IEEE128
            handling without vsx go with libcall.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.target/powerpc/pr114402.c: New test.

Diff:
---
 gcc/config/rs6000/rs6000.cc                 |  4 ++--
 gcc/testsuite/gcc.target/powerpc/pr114402.c | 16 ++++++++++++++++
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index e713a1e1d570..d18e262d81de 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -15283,7 +15283,7 @@ rs6000_generate_compare (rtx cmp, machine_mode mode)
   rtx op0 = XEXP (cmp, 0);
   rtx op1 = XEXP (cmp, 1);
 
-  if (!TARGET_FLOAT128_HW && FLOAT128_VECTOR_P (mode))
+  if (!TARGET_FLOAT128_HW && FLOAT128_IEEE_P (mode))
     comp_mode = CCmode;
   else if (FLOAT_MODE_P (mode))
     comp_mode = CCFPmode;
@@ -15315,7 +15315,7 @@ rs6000_generate_compare (rtx cmp, machine_mode mode)
 
   /* IEEE 128-bit support in VSX registers when we do not have hardware
      support.  */
-  if (!TARGET_FLOAT128_HW && FLOAT128_VECTOR_P (mode))
+  if (!TARGET_FLOAT128_HW && FLOAT128_IEEE_P (mode))
     {
       rtx libfunc = NULL_RTX;
       bool check_nan = false;
diff --git a/gcc/testsuite/gcc.target/powerpc/pr114402.c 
b/gcc/testsuite/gcc.target/powerpc/pr114402.c
new file mode 100644
index 000000000000..9323c5ee991d
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr114402.c
@@ -0,0 +1,16 @@
+/* Explicitly disable VSX when VSX is on.  */
+/* { dg-options "-mno-vsx" { target powerpc_vsx } } */
+
+/* Verify there is no ICE.  */
+
+long double a;
+long double b;
+
+int
+foo ()
+{
+  if (a > b)
+    return 0;
+  else
+    return 1;
+}