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| author | kelefth <konstantinos.eleftheriou@vrull.eu> | 2025-03-13 11:49:39 +0100 |
|---|---|---|
| committer | Philipp Tomsich <philipp.tomsich@vrull.eu> | 2025-04-18 10:42:00 +0200 |
| commit | 7e628ff49f7f890d5337369d7b4f8e21a1f17029 (patch) | |
| tree | db319a5c5c1e78ab256af31b386701b89ab20745 /gcc | |
| parent | 19af15ba7ad041b58b7926775cce81be9f5ec013 (diff) | |
| download | gcc-7e628ff49f7f890d5337369d7b4f8e21a1f17029.zip gcc-7e628ff49f7f890d5337369d7b4f8e21a1f17029.tar.gz gcc-7e628ff49f7f890d5337369d7b4f8e21a1f17029.tar.bz2 | |
avoid-store-forwarding: Fix reg init on load-elimination [PR119160]
In the case that we are eliminating the load instruction, we use zero_extend
for the initialization of the base register for the zero-offset store.
This causes issues when the store and the load use the same mode,
as we are trying to generate a zero_extend with the same inner and
outer modes.
This patch fixes the issue by zero-extending the value stored in the
base register only when the load's mode is wider than the store's mode.
PR rtl-optimization/119160
gcc/ChangeLog:
* avoid-store-forwarding.cc (process_store_forwarding):
Zero-extend the value stored in the base register, in case
of load-elimination, only when the mode of the destination
is wider.
gcc/testsuite/ChangeLog:
* gcc.dg/pr119160.c: New test.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/avoid-store-forwarding.cc | 11 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.dg/pr119160.c | 26 |
2 files changed, 34 insertions, 3 deletions
diff --git a/gcc/avoid-store-forwarding.cc b/gcc/avoid-store-forwarding.cc index 34a7bba..ded8d7e 100644 --- a/gcc/avoid-store-forwarding.cc +++ b/gcc/avoid-store-forwarding.cc @@ -238,10 +238,15 @@ process_store_forwarding (vec<store_fwd_info> &stores, rtx_insn *load_insn, { start_sequence (); - rtx ext0 = gen_rtx_ZERO_EXTEND (GET_MODE (dest), it->mov_reg); - if (ext0) + machine_mode dest_mode = GET_MODE (dest); + rtx base_reg = it->mov_reg; + if (known_gt (GET_MODE_BITSIZE (dest_mode), + GET_MODE_BITSIZE (GET_MODE (it->mov_reg)))) + base_reg = gen_rtx_ZERO_EXTEND (dest_mode, it->mov_reg); + + if (base_reg) { - rtx_insn *move0 = emit_move_insn (dest, ext0); + rtx_insn *move0 = emit_move_insn (dest, base_reg); if (recog_memoized (move0) >= 0) { insns = get_insns (); diff --git a/gcc/testsuite/gcc.dg/pr119160.c b/gcc/testsuite/gcc.dg/pr119160.c new file mode 100644 index 0000000..b4629a1 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr119160.c @@ -0,0 +1,26 @@ +/* { dg-do run } */ +/* { dg-options "-O2 -finstrument-functions-once -favoid-store-forwarding -fnon-call-exceptions -fschedule-insns -mgeneral-regs-only -Wno-psabi" } */ + +typedef __attribute__((__vector_size__ (32))) int V; + +void +foo (V v, V, V, V *r) +{ + V u = (V){} + v[0]; + *r = u; +} + +__attribute__((__noipa__)) void +bar(int x) +{ + if (x != 2) __builtin_abort(); +} + +int +main () +{ + V x; + foo ((V){ 2, 3 }, (V){ }, (V){ }, &x); + for (unsigned i = 0; i < sizeof(x)/sizeof(x[0]); i++) + bar(x[i]); +}
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