The following patch solves
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121007
The patch was successfully bootstrapped and tested on amd64, arm64, ppc64le.
commit 06c41504bd4a23c3f5848793fda503c30fe51353
Author: Vladimir N. Makarov <vmaka...@redhat.com>
Date: Fri Jul 11 11:27:54 2025 -0400
[PR121007, LRA]: Fall back to reload of whole inner address in PR case and constrain iteration number of address reloads
gcc/ChangeLog:
* lra-constraints.cc (process_address_1): When changing base reg
on a reg of the base class, fall back to reload of whole inner address.
(process_address): Constrain the iteration number.
gcc/testsuite/ChangeLog:
* gcc.target/powerpc/pr121007.c: New.
diff --git a/gcc/lra-constraints.cc b/gcc/lra-constraints.cc
index 68aaf863a97..274b52cd617 100644
--- a/gcc/lra-constraints.cc
+++ b/gcc/lra-constraints.cc
@@ -3930,6 +3930,16 @@ process_address_1 (int nop, bool check_only_p,
enum reg_class cl;
rtx set;
rtx_insn *insns, *last_insn;
+
+ cl = base_reg_class (ad.mode, ad.as, ad.base_outer_code,
+ get_index_code (&ad), curr_insn);
+
+ if (REG_P (*ad.base_term)
+ && ira_class_subset_p[get_reg_class (REGNO (*ad.base_term))][cl])
+ /* It seems base reg is already in the base reg class and changing it
+ does not make a progress. So reload the whole inner address. */
+ goto reload_inner_addr;
+
/* Try to reload base into register only if the base is invalid
for the address but with valid offset, case (4) above. */
start_sequence ();
@@ -3975,8 +3985,6 @@ process_address_1 (int nop, bool check_only_p,
{
*ad.base_term = XEXP (SET_SRC (set), 0);
*ad.disp_term = XEXP (SET_SRC (set), 1);
- cl = base_reg_class (ad.mode, ad.as, ad.base_outer_code,
- get_index_code (&ad), curr_insn);
regno = REGNO (*ad.base_term);
if (regno >= FIRST_PSEUDO_REGISTER
&& cl != lra_get_allocno_class (regno))
@@ -4019,11 +4027,11 @@ process_address_1 (int nop, bool check_only_p,
}
else
{
- enum reg_class cl = base_reg_class (ad.mode, ad.as,
- SCRATCH, SCRATCH,
- curr_insn);
- rtx addr = *ad.inner;
-
+ enum reg_class cl;
+ rtx addr;
+ reload_inner_addr:
+ cl = base_reg_class (ad.mode, ad.as, SCRATCH, SCRATCH, curr_insn);
+ addr = *ad.inner;
new_reg = lra_create_new_reg (Pmode, NULL_RTX, cl, NULL, "addr");
/* addr => new_base. */
lra_emit_move (new_reg, addr);
@@ -4044,14 +4052,21 @@ process_address (int nop, bool check_only_p,
rtx_insn **before, rtx_insn **after)
{
bool res = false;
-
- while (process_address_1 (nop, check_only_p, before, after))
+ /* Use enough iterations to process all address parts: */
+ for (int i = 0; i < 10; i++)
{
- if (check_only_p)
- return true;
- res = true;
+ if (!process_address_1 (nop, check_only_p, before, after))
+ {
+ return res;
+ }
+ else
+ {
+ if (check_only_p)
+ return true;
+ res = true;
+ }
}
- return res;
+ fatal_insn ("unable to reload address in ", curr_insn);
}
/* Override the generic address_reload_context in order to
diff --git a/gcc/testsuite/gcc.target/powerpc/pr121007.c b/gcc/testsuite/gcc.target/powerpc/pr121007.c
new file mode 100644
index 00000000000..9e6b1be7911
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr121007.c
@@ -0,0 +1,40 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mdejagnu-cpu=power9" } */
+
+typedef struct { int a; } A;
+unsigned char *a;
+char b;
+int c;
+void foo (vector char, vector char, vector char);
+
+void
+bar (long stride)
+{
+ vector char v0, v1, v2, v3, v5;
+ vector char r0 = __builtin_vec_vsx_ld (0, a);
+ vector char r2 = __builtin_vec_vsx_ld (2 * stride, a - 3);
+ vector char r3 = __builtin_vec_vsx_ld (3 * stride, a - 3);
+ vector char r4;
+ vector char r6 = __builtin_vec_vsx_ld (6 * stride, a - 3);
+ vector char r7 = __builtin_vec_vsx_ld (7 * stride, a - 3);
+ vector char r14, h, i, j;
+ if (b)
+ return;
+ v1 = __builtin_vec_vsx_ld (9 * stride, a);
+ v2 = __builtin_vec_vsx_ld (10 * stride, a - 3);
+ v3 = __builtin_vec_vsx_ld (11 * stride, a - 3);
+ r3 = __builtin_vec_mergeh (r3, v3);
+ v5 = __builtin_vec_mergel (r2, r6);
+ r14 = __builtin_vec_mergeh (r3, r7);
+ r4 = __builtin_vec_mergeh (v2, r14);
+ v0 = __builtin_vec_mergeh (r0, r4);
+ union { unsigned char a[16]; A b; } temp;
+ vector signed char k;
+ h = __builtin_vec_ld (0, temp.a);
+ i = __builtin_vec_splat (h, 1);
+ temp.b.a = c;
+ k = __builtin_vec_ld (0, (signed char *) temp.a);
+ j = __builtin_vec_and (i, (vector char) k);
+ foo (v1, v0, j);
+ foo (v1, v5, j);
+}
