Hi,
This patch looks good to me.
This patch significantly simplifies the logic, by directly using vcmpnez
which appears to achieve the same result!
Thanks for fixing this.
I think we will wait for Segher comments
Regards,
Manjunath S Matti.
On 20/11/25 12:04 pm, Vijay Shankar wrote:
Changes from v1:
* Corrected commit message formatting and fixed typo.
This patch removes redundant vector compare instructions and logic
from the vec_first_mismatch_or_eos_index intrinsic.
Currently, GCC generates extra vcmpneb instructions and additional
masking logic (xxland, xxlorc) to handle EOS and mismatch comparisons.
However, a single vcmpnezb instruction already suffices, as it covers
both By eliminating the redundant comparisons (vcmpneb) and the
associated logic (xxland/xxlorc) we produce shorter,
more efficient code.
Bootstrapped and tested on powerpc64le-linux-gnu with no regressions.
2025-10-22 Vijay Shankar <[email protected]>
gcc/ChangeLog:
PR target/116004
* config/rs6000/vsx.md (first_mismatch_or_eos_index): Remove
redundant
emit_insns.
---
gcc/config/rs6000/vsx.md | 22 +++-------------------
1 file changed, 3 insertions(+), 19 deletions(-)
diff --git a/gcc/config/rs6000/vsx.md b/gcc/config/rs6000/vsx.md
index dd3573b80..cac1e6080 100644
--- a/gcc/config/rs6000/vsx.md
+++ b/gcc/config/rs6000/vsx.md
@@ -5668,29 +5668,13 @@
"TARGET_P9_VECTOR"
{
int sh;
- rtx cmpz1_result = gen_reg_rtx (<MODE>mode);
- rtx cmpz2_result = gen_reg_rtx (<MODE>mode);
- rtx cmpz_result = gen_reg_rtx (<MODE>mode);
- rtx not_cmpz_result = gen_reg_rtx (<MODE>mode);
- rtx and_result = gen_reg_rtx (<MODE>mode);
rtx result = gen_reg_rtx (<MODE>mode);
- rtx vzero = gen_reg_rtx (<MODE>mode);
-
- /* Vector with zeros in elements that correspond to zeros in operands. */
- emit_move_insn (vzero, CONST0_RTX (<MODE>mode));
- emit_insn (gen_vcmpne<VSX_EXTRACT_WIDTH> (cmpz1_result, operands[1], vzero));
- emit_insn (gen_vcmpne<VSX_EXTRACT_WIDTH> (cmpz2_result, operands[2], vzero));
- emit_insn (gen_and<mode>3 (and_result, cmpz1_result, cmpz2_result));
+ /* Vector with ones in elements that match or elements corresponding to zeros
+ in operands. */
- /* Vector with ones in elments that match. */
- emit_insn (gen_vcmpnez<VSX_EXTRACT_WIDTH> (cmpz_result, operands[1],
+ emit_insn (gen_vcmpnez<VSX_EXTRACT_WIDTH> (result, operands[1],
operands[2]));
- emit_insn (gen_one_cmpl<mode>2 (not_cmpz_result, cmpz_result));
-
- /* Create vector with ones in elements where there was a zero in one of
- the source elements or the elements did not match. */
- emit_insn (gen_nand<mode>3 (result, and_result, not_cmpz_result));
sh = GET_MODE_SIZE (GET_MODE_INNER (<MODE>mode)) / 2;
if (<MODE>mode == V16QImode)
