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.
2025-10-22 Vijay Shankar <[email protected]> Bootstrapped and tested on powerpc64le-linux-gnu with no regressions. 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..dbec55e38 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 elments 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) -- 2.47.3
