Hello,
On 21/09/2025 00:30, Sam James wrote:
Jussi Kivilinna <jussi.kivili...@iki.fi> writes:
* configure.ac (gcry_cv_riscv_vsha2cl_intrinsics_work)
(gcry_cv_riscv_vaes_vs_intrinsics_work): Run check with '-fno-lto' compiler
flag.
I assume this is because of https://gcc.gnu.org/PR110812? If so, a
comment referencing it would be nice.
Issue is with compiling with LTO is not generating target architecture (RISCV) instructions in
output. This applies to both GCC and clang, and is not really a compiler bug but problem with these
checks. Result was that 'configure' did not detect broken vsha2cl/vaes intrinsics when LTO was
enabled for compiler. I'll change "target instructions" in comment to "RISCV
instructions in compiler output" to clarify.
That GCC issue is for linker not knowing correct RISCV microarchitecture during
linking for LTO, so different issue. I did notice that GCC could not build
RISCV libgcrypt with LTO and errors I got looked the same as in that bug
report. Clang LTO build did work... but with following warning during linking
phase:
Hard-float 'd' ABI can't be used for a target that doesn't support the D
instruction set extension (ignoring target-abi)
-Jussi
--
Signed-off-by: Jussi Kivilinna <jussi.kivili...@iki.fi>
---
configure.ac | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/configure.ac b/configure.ac
index 80d38496..90c513be 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2934,6 +2934,9 @@ if test "$gcry_cv_cc_riscv_vector_crypto_intrinsics" =
"yes" ||
CFLAGS="$CFLAGS -O2 -march=$MARCH_RVA23U64_WITH_VEC_CRYPTO -mstrict-align"
fi
+ # Disable LTO optimization to generate target instructions
+ CFLAGS="$CFLAGS -fno-lto"
+
AC_CACHE_CHECK([whether compiler has working RISC-V __riscv_vsha2cl
intrinsics],
[gcry_cv_riscv_vsha2cl_intrinsics_work],
[gcry_cv_riscv_vsha2cl_intrinsics_work=no
@@ -2981,6 +2984,9 @@ if test "$gcry_cv_cc_riscv_vector_crypto_intrinsics" =
"yes" ||
CFLAGS="$CFLAGS -O2"
fi
+ # Disable LTO optimization to generate target instructions
+ CFLAGS="$CFLAGS -fno-lto"
+
AC_CACHE_CHECK([whether compiler has working RISC-V __riscv_vaes*_vs
intrinsics],
[gcry_cv_riscv_vaes_vs_intrinsics_work],
[gcry_cv_riscv_vaes_vs_intrinsics_work=no
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