From cdb34bf5dd10df967b7f72a502a48cc34e284ef0 Mon Sep 17 00:00:00 2001 From: Robin Dapp Date: Fri, 1 Dec 2023 09:45:29 +0100 Subject: [PATCH] RISC-V: Fix rawmemchr implementation. This fixes a bug in the rawmemchr implementation by incrementing the source address by vl * element_size instead of just vl. This is normally harmless as we will just scan the same region more than once but, in combination with an older qemu version, will lead to an execution failure in SPEC2017. gcc/ChangeLog: * config/riscv/riscv-string.cc (expand_rawmemchr): Increment source address by vl * element_size. --- gcc/config/riscv/riscv-string.cc | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/gcc/config/riscv/riscv-string.cc b/gcc/config/riscv/riscv-string.cc index f3a4d3ddd47f..594ff49fc5ac 100644 --- a/gcc/config/riscv/riscv-string.cc +++ b/gcc/config/riscv/riscv-string.cc @@ -1017,6 +1017,8 @@ expand_rawmemchr (machine_mode mode, rtx dst, rtx src, rtx pat) machine_mode mask_mode = riscv_vector::get_mask_mode (vmode); rtx cnt = gen_reg_rtx (Pmode); + emit_move_insn (cnt, CONST0_RTX (Pmode)); + rtx end = gen_reg_rtx (Pmode); rtx vec = gen_reg_rtx (vmode); rtx mask = gen_reg_rtx (mask_mode); @@ -1033,6 +1035,11 @@ expand_rawmemchr (machine_mode mode, rtx dst, rtx src, rtx pat) rtx vsrc = change_address (src, vmode, src_addr); + /* Bump the pointer. */ + rtx step = gen_reg_rtx (Pmode); + emit_insn (gen_rtx_SET (step, gen_rtx_ASHIFT (Pmode, cnt, GEN_INT (shift)))); + emit_insn (gen_rtx_SET (src_addr, gen_rtx_PLUS (Pmode, src_addr, step))); + /* Emit a first-fault load. */ rtx vlops[] = {vec, vsrc}; emit_vlmax_insn (code_for_pred_fault_load (vmode), @@ -1055,16 +1062,10 @@ expand_rawmemchr (machine_mode mode, rtx dst, rtx src, rtx pat) emit_nonvlmax_insn (code_for_pred_ffs (mask_mode, Pmode), riscv_vector::CPOP_OP, vfops, cnt); - /* Bump the pointer. */ - emit_insn (gen_rtx_SET (src_addr, gen_rtx_PLUS (Pmode, src_addr, cnt))); - /* Emit the loop condition. */ rtx test = gen_rtx_LT (VOIDmode, end, const0_rtx); emit_jump_insn (gen_cbranch4 (Pmode, test, end, const0_rtx, loop)); - /* We overran by CNT, subtract it. */ - emit_insn (gen_rtx_SET (src_addr, gen_rtx_MINUS (Pmode, src_addr, cnt))); - /* We found something at SRC + END * [1,2,4,8]. */ emit_insn (gen_rtx_SET (end, gen_rtx_ASHIFT (Pmode, end, GEN_INT (shift)))); emit_insn (gen_rtx_SET (dst, gen_rtx_PLUS (Pmode, src_addr, end))); -- 2.47.2