[Bug c/119830] New: RISC-V:Internal Compiler Error on RISC-V Windows Toolchain (32-bit program) with -march=rv64gc_zbb_zbs

[bigmagicreadsun at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119830

            Bug ID: 119830
           Summary: RISC-V:Internal Compiler Error on RISC-V Windows
                    Toolchain (32-bit program) with -march=rv64gc_zbb_zbs
           Product: gcc
           Version: 14.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: bigmagicreadsun at gmail dot com
  Target Milestone: ---

Description:

When compiling the following code using a RISC-V Windows toolchain (32-bit
program) with -march=rv64gc_zbb_zbs -mabi=lp64d -O3, an internal compiler error
occurs:

<C>
#include <stdint.h>
void test(int32_t N, int16_t* A, int16_t val) {
    int32_t i, j;
    for (i = 0; i < N; i++) {
        for (j = 0; j < N; j++) {
            A[i * N + j] += val;
        }
    }
}
Command & Error:

<BASH>
riscv64-unknown-elf-gcc.exe -Ofast -march=rv64gc_zbb_zbs -mabi=lp64d -c .\xxx.c
-fdump-rtl-all -freport-bug
.\xxx.c: In function 'test':
.\xxx.c:10:1: error: unrecognizable insn:
(insn 264 263 265 28 (set (reg:DI 419)
        (and:DI (reg:DI 421)
            (const_int 2147483647 [0x7fffffff]))) -1
     (expr_list:REG_EQUAL (const_int -4294901761 [0xffffffff0000ffff])
        (nil)))
during RTL pass: vregs
xxx.c.267r.vregs
internal compiler error: in extract_insn, at recog.cc:2812
Additional Context:

Comparing the RISC-V Linux toolchain’s RTL dump (Godbolt
link:https://godbolt.org/z/rcooKfc1n), the correct insn uses the bclridi
template:
<LISP>
(insn 329 328 330 28 (set (reg:DI 413)
        (and:DI (reg:DI 415)
            (const_int -2147483649 [0xffffffff7fffffff]))) 630 {*bclridi}
     (expr_list:REG_EQUAL (const_int -4294901761 [0xffffffff0000ffff])...))
The Windows toolchain produces a mismatched insn:
<LISP>
(insn 264 [...] (const_int 2147483647 [0x7fffffff])))  ; Not matching bclridi
The discrepancy in the generated and constant (2147483647 vs. -2147483649)
causes failure to match the bclridi pattern, triggering the ICE.

Question: Why does the Windows toolchain generate inconsistent RTL patterns
compared to Linux for the bclridi instruction template?

Compiler Version: riscv64-unknown-elf-gcc 14.2.1

Reproduction Steps:

Compile the code with -march=rv64gc_zbb_zbs -mabi=lp64d -O3.
Observe RTL differences in the vregs pass.
This includes all critical details and allows GCC developers to investigate
architecture-specific code generation differences. Let me know if you need
further adjustments.