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| author | Paolo Bonzini <pbonzini@redhat.com> | 2023-10-27 05:57:31 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2024-05-07 08:50:39 +0200 |
| commit | 15957eb9efe2da67c796612cead95cba28ba9bda (patch) | |
| tree | b4eece3d4afe1f87a483b1f0a856540a85f08dd3 /backends | |
| parent | b776569a53f70ab4661ed627756385b05dcaf75e (diff) | |
| download | qemu-15957eb9efe2da67c796612cead95cba28ba9bda.zip qemu-15957eb9efe2da67c796612cead95cba28ba9bda.tar.gz qemu-15957eb9efe2da67c796612cead95cba28ba9bda.tar.bz2 | |
target/i386: use TSTEQ/TSTNE to test low bits
When testing the sign bit or equality to zero of a partial register, it
is useful to use a single TSTEQ or TSTNE operation. It can also be used
to test the parity flag, using bit 0 of the population count.
Do not do this for target_ulong-sized values however; the optimizer would
produce a comparison against zero anyway, and it avoids shifts by 64
which are undefined behavior.
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'backends')
0 files changed, 0 insertions, 0 deletions