From 526efb6bfc148e1ca5d1ec7dd101cb18fdca5302 Mon Sep 17 00:00:00 2001 From: Richard Sandiford Date: Mon, 21 Jul 2025 15:41:03 +0100 Subject: [PATCH] aarch64: Fix endianness of DFmode vector constants aarch64_simd_valid_imm tries to decompose a constant into a repeating series of 64 bits, since most Advanced SIMD and SVE immediate forms require that. (The exceptions are handled first.) It does this by building up a byte-level register image, lsb first. If the image does turn out to repeat every 64 bits, it loads the first 64 bits into an integer. At this point, endianness has mostly been dealt with. Endianness applies to transfers between registers and memory, whereas at this point we're dealing purely with register values. However, one of things we try is to bitcast the value to a float and use FMOV. This involves splitting the value into 32-bit chunks (stored as longs) and passing them to real_from_target. The problem being fixed by this patch is that, when a value spans multiple 32-bit chunks, real_from_target expects them to be in memory rather than register order. Thus index 0 is the most significant chunk if FLOAT_WORDS_BIG_ENDIAN and the least significant chunk otherwise. This fixes aarch64/sve/cond_fadd_1.c and various other tests for aarch64_be-elf. gcc/ * config/aarch64/aarch64.cc (aarch64_simd_valid_imm): Account for FLOAT_WORDS_BIG_ENDIAN when building a floating-point value. (cherry picked from commit 82dd19890b6139c4bac2385068a68613920ae1a2) --- gcc/config/aarch64/aarch64.cc | 2 ++ 1 file changed, 2 insertions(+) diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc index 4f68fe2e0d5..cfbf0a7eeba 100644 --- a/gcc/config/aarch64/aarch64.cc +++ b/gcc/config/aarch64/aarch64.cc @@ -23531,6 +23531,8 @@ aarch64_simd_valid_imm (rtx op, simd_immediate_info *info, long int as_long_ints[2]; as_long_ints[0] = ival & 0xFFFFFFFF; as_long_ints[1] = (ival >> 32) & 0xFFFFFFFF; + if (imode == DImode && FLOAT_WORDS_BIG_ENDIAN) + std::swap (as_long_ints[0], as_long_ints[1]); REAL_VALUE_TYPE r; real_from_target (&r, as_long_ints, fmode); -- 2.47.2