[gcc r14-9068] GCN: Conditionalize 'define_expand "reduc_<fexpander>_scal_<mode>"' on '!TARGET_RDNA2_PLUS' [PR11361

[gcc r14-9068] GCN: Conditionalize 'define_expand "reduc_<fexpander>_scal_<mode>"' on '!TARGET_RDNA2_PLUS' [PR11361

[Thomas Schwinge]

https://gcc.gnu.org/g:641b50bffc06123853a1421c0dd5a318c353fd85

commit r14-9068-g641b50bffc06123853a1421c0dd5a318c353fd85
Author: Thomas Schwinge <tschwinge@baylibre.com>
Date:   Fri Feb 16 13:04:00 2024 +0100

    GCN: Conditionalize 'define_expand "reduc_<fexpander>_scal_<mode>"' on '!TARGET_RDNA2_PLUS' [PR113615]
    
    On top of commit c7ec7bd1c6590cf4eed267feab490288e0b8d691
    "amdgcn: add -march=gfx1030 EXPERIMENTAL" conditionalizing
    'define_expand "reduc_<reduc_op>_scal_<mode>"' on
    '!TARGET_RDNA2' (later: '!TARGET_RDNA2_PLUS'), we then did similar in
    commit 7cc2262ec9a410dc56d1c1c6b950c922e14f621d
    "gcn/gcn-valu.md: Disable fold_left_plus for TARGET_RDNA2_PLUS [PR113615]"
    to conditionalize 'define_expand "fold_left_plus_<mode>"' on
    '!TARGET_RDNA2_PLUS', but I found we also need to conditionalize the related
    'define_expand "reduc_<fexpander>_scal_<mode>"' on '!TARGET_RDNA2_PLUS', to
    avoid ICEs like:
    
        [...]/gcc.dg/vect/pr108608.c: In function 'foo':
        [...]/gcc.dg/vect/pr108608.c:9:1: error: unrecognizable insn:
        (insn 34 33 35 2 (set (reg:V64DF 723)
                (unspec:V64DF [
                        (reg:V64DF 690 [ vect_m_11.20 ])
                        (const_int 1 [0x1])
                    ] UNSPEC_MOV_DPP_SHR)) -1
             (nil))
        during RTL pass: vregs
    
    Similar for 'gcc.dg/vect/vect-fmax-2.c', 'gcc.dg/vect/vect-fmin-2.c', and
    'UNSPEC_SMAX_DPP_SHR' for 'gcc.dg/vect/vect-fmax-1.c', and
    'UNSPEC_SMIN_DPP_SHR' for 'gcc.dg/vect/vect-fmin-1.c', when running 'vect.exp'
    for 'check-gcc-c'.
    
            PR target/113615
            gcc/
            * config/gcn/gcn-valu.md (define_expand "reduc_<fexpander>_scal_<mode>"):
            Conditionalize on '!TARGET_RDNA2_PLUS'.
            * config/gcn/gcn.cc (gcn_expand_dpp_shr_insn)
            (gcn_expand_reduc_scalar):
            'gcc_checking_assert (!TARGET_RDNA2_PLUS);'.

Diff:
---
 gcc/config/gcn/gcn-valu.md | 2 +-
 gcc/config/gcn/gcn.cc      | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/gcc/config/gcn/gcn-valu.md b/gcc/config/gcn/gcn-valu.md
index 59e27d0aed79..e8381d28c1b0 100644
--- a/gcc/config/gcn/gcn-valu.md
+++ b/gcc/config/gcn/gcn-valu.md
@@ -4261,7 +4261,7 @@
   [(match_operand:<SCALAR_MODE> 0 "register_operand")
    (fminmaxop:V_FP
      (match_operand:V_FP 1 "register_operand"))]
-  ""
+  "!TARGET_RDNA2_PLUS"
   {
     /* fmin/fmax are identical to smin/smax.  */
     emit_insn (gen_reduc_<expander>_scal_<mode> (operands[0], operands[1]));
diff --git a/gcc/config/gcn/gcn.cc b/gcc/config/gcn/gcn.cc
index 4559d6932d4a..bc076d1120d9 100644
--- a/gcc/config/gcn/gcn.cc
+++ b/gcc/config/gcn/gcn.cc
@@ -5448,6 +5448,8 @@ char *
 gcn_expand_dpp_shr_insn (machine_mode mode, const char *insn,
 			 int unspec, int shift)
 {
+  gcc_checking_assert (!TARGET_RDNA2_PLUS);
+
   static char buf[128];
   const char *dpp;
   const char *vcc_in = "";
@@ -5509,6 +5511,8 @@ gcn_expand_dpp_shr_insn (machine_mode mode, const char *insn,
 rtx
 gcn_expand_reduc_scalar (machine_mode mode, rtx src, int unspec)
 {
+  gcc_checking_assert (!TARGET_RDNA2_PLUS);
+
   machine_mode orig_mode = mode;
   machine_mode scalar_mode = GET_MODE_INNER (mode);
   int vf = GET_MODE_NUNITS (mode);