[gcc r10-10959] rs6000: Adjust mov optabs for opaque modes [PR103353]

[Kewen Lin <linkw@gcc.gnu.org>]

https://gcc.gnu.org/g:501fba663052b0b4a1eb6a42c32b74c254cbedbc

commit r10-10959-g501fba663052b0b4a1eb6a42c32b74c254cbedbc
Author: Kewen Lin <linkw@linux.ibm.com>
Date:   Tue Aug 23 03:31:17 2022 -0500

    rs6000: Adjust mov optabs for opaque modes [PR103353]
    
    As PR103353 shows, we may want to continue to expand built-in
    function __builtin_vsx_lxvp, even if we have already emitted
    error messages about some missing required conditions.  As
    shown in that PR, without one explicit mov optab on OOmode
    provided, it would call emit_move_insn recursively.
    
    So this patch is to allow the mov pattern to be generated during
    expanding phase if compiler has already seen errors.
    
            PR target/103353
    
    gcc/ChangeLog:
    
            * config/rs6000/mma.md (define_expand movpoi): Move TARGET_MMA condition
            check to preparation statements and add handlings for !TARGET_MMA.
            (define_expand movpxi): Likewise.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.target/powerpc/pr103353.c: New test.
    
    (cherry picked from commit 9367e3a65f874dffc8f8a3b6760e77fd9ed67117)

Diff:
---
 gcc/config/rs6000/mma.md                    | 39 ++++++++++++++++++++++++-----
 gcc/testsuite/gcc.target/powerpc/pr103353.c | 22 ++++++++++++++++
 2 files changed, 55 insertions(+), 6 deletions(-)

diff --git a/gcc/config/rs6000/mma.md b/gcc/config/rs6000/mma.md
index 27f64d2cb7c..c6e07e5dd78 100644
--- a/gcc/config/rs6000/mma.md
+++ b/gcc/config/rs6000/mma.md
@@ -283,10 +283,25 @@
 (define_expand "movpoi"
   [(set (match_operand:POI 0 "nonimmediate_operand")
 	(match_operand:POI 1 "input_operand"))]
-  "TARGET_MMA"
+  ""
 {
-  rs6000_emit_move (operands[0], operands[1], POImode);
-  DONE;
+  if (TARGET_MMA)
+    {
+      rs6000_emit_move (operands[0], operands[1], POImode);
+      DONE;
+    }
+  else if (currently_expanding_to_rtl && seen_error ())
+    {
+      /* PR103353 shows we may want to continue to expand the __builtin_vsx_lxvp
+	 built-in function, even if we have already emitted error messages about
+	 some missing required conditions.  As shown in that PR, without one
+	 explicit mov optab on POImode provided, it would call emit_move_insn
+	 recursively.  So we allow this pattern to be generated when we are
+	 expanding to RTL and have seen errors.  It would not cause further ICEs
+	 as the compilation would stop soon after expanding.  */
+    }
+  else
+    gcc_unreachable ();
 })
 
 (define_insn_and_split "*movpoi"
@@ -323,10 +338,22 @@
 (define_expand "movpxi"
   [(set (match_operand:PXI 0 "nonimmediate_operand")
 	(match_operand:PXI 1 "input_operand"))]
-  "TARGET_MMA"
+  ""
 {
-  rs6000_emit_move (operands[0], operands[1], PXImode);
-  DONE;
+  if (TARGET_MMA)
+    {
+      rs6000_emit_move (operands[0], operands[1], PXImode);
+      DONE;
+    }
+  else if (currently_expanding_to_rtl && seen_error ())
+    {
+      /* PR103353 shows we may want to continue to expand the __builtin_vsx_lxvp
+	 built-in function, even if we have already emitted error messages about
+	 some missing required conditions.  So do the same handlings for PXImode
+	 as POImode here.  */
+    }
+  else
+    gcc_unreachable ();
 })
 
 (define_insn_and_split "*movpxi"
diff --git a/gcc/testsuite/gcc.target/powerpc/pr103353.c b/gcc/testsuite/gcc.target/powerpc/pr103353.c
new file mode 100644
index 00000000000..5d519fb1b7b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr103353.c
@@ -0,0 +1,22 @@
+/* { dg-require-effective-target powerpc_altivec_ok } */
+/* If the default cpu type is power10 or later, MMA is enabled by default.
+   To keep the test point available all the time, this case specifies
+   -mdejagnu-cpu=power6 to make it be tested without MMA.  */
+/* { dg-options "-maltivec -mdejagnu-cpu=power6" } */
+
+/* Verify there is no ICE and don't check the error messages on MMA
+   requirement since they could be fragile and are not test points
+   of this case.  */
+/* { dg-excess-errors "pr103353" } */
+
+void
+foo (__vector_pair *dst, double *x)
+{
+  dst[0] = __builtin_vsx_lxvp (0, (__vector_pair *)(void *)x);
+}
+
+void
+bar (__vector_pair *src, double *x)
+{
+  __builtin_vsx_stxvp (src[0], 0, (__vector_pair *)(void *)x);
+}