Modern processors has multiple way instruction decoders
For x86, icelake/zen3 has 5 uops, so for small loop with <= 4
instructions (usually has 3 uops with a cmp/jmp pair that can be
macro-fused), the decoder would have 2 uops bubble for each iteration
and the pipeline could not be fully utilized.
Therefore, this patch enables loop unrolling for small size loop at O2
to fullfill the decoder as much as possible. It turns on rtl loop
unrolling when targetm.loop_unroll_adjust exists and O2 plus speed only.
In x86 backend the default behavior is to unroll small loops with less
than 4 insns by 1 time.
This improves 548.exchange2 by 9% on icelake and 7.4% on zen3 with
0.9% codesize increment. For other benchmarks the variants are minor
and overall codesize increased by 0.2%.
The kernel image size increased by 0.06%, and no impact on eembc.
gcc/ChangeLog:
* common/config/i386/i386-common.cc (ix86_optimization_table):
Enable small loop unroll at O2 by default.
* config/i386/i386.cc (ix86_loop_unroll_adjust): Adjust unroll
factor if -munroll-only-small-loops enabled and -funroll-loops/
-funroll-all-loops are disabled.
* config/i386/i386.h (struct processor_costs): Add 2 field
small_unroll_ninsns and small_unroll_factor.
* config/i386/i386.opt: Add -munroll-only-small-loops.
* doc/invoke.texi: Document -munroll-only-small-loops.
* loop-init.cc (pass_rtl_unroll_loops::gate): Enable rtl
loop unrolling for -O2-speed and above if target hook
loop_unroll_adjust exists.
(pass_rtl_unroll_loops::execute): Set UAP_UNROLL flag
when target hook loop_unroll_adjust exists.
* config/i386/x86-tune-costs.h: Update all processor costs
with small_unroll_ninsns = 4 and small_unroll_factor = 2.
gcc/testsuite/ChangeLog:
* gcc.dg/guality/loop-1.c: Add additional option
-mno-unroll-only-small-loops.
* gcc.target/i386/pr86270.c: Add -mno-unroll-only-small-loops.
* gcc.target/i386/pr93002.c: Likewise.
We set up INLINE_HINT_known_hot hint only when we have profile feedback,
now add function attribute judgement for it, when both caller and callee
have __attribute__((hot)), we will also set up INLINE_HINT_known_hot hint
for it.
With this patch applied,
ADL Multi-copy: 538.imagic_r 16.7%
ICX Multi-copy: 538.imagic_r 15.2%
CLX Multi-copy: 538.imagic_r 12.7%
Znver3 Multi-copy: 538.imagic_r 10.6%
Arm Multi-copy: 538.imagic_r 13.4%
gcc/ChangeLog
* ipa-inline-analysis.cc (do_estimate_edge_time): Add function attribute
judgement for INLINE_HINT_known_hot hint.
gcc/testsuite/ChangeLog:
* gcc.dg/ipa/inlinehint-6.c: New test.
and fix bugs
- add-fp-model-options.patch: New file
- enable-simd-math.patch: Enable simd math library in C and Fortran
- fix-CTOR-vectorization.patch: New file
- fix-range-set-by-vectorization-on-niter-IVs.patch: New file
- medium-code-mode.patch: Fix bugs when used with fpic
- optabs-Dont-use-scalar-conversions-for-vectors.patch: New file
- PR92429-do-not-fold-when-updating.patch: New file
- redundant-loop-elimination.patch: Fix some programming specifications
- fix-ICE-in-vect.patch: New file
- Fix-type-mismatch-in-SLPed-constructors.patch: New file
- add-check-for-pressure-in-sche1.patch: New file
- revert-moutline-atomics.patch: New file
- fix-ICE-in-eliminate-stmt.patch: New file
- revise-type-before-build-MULT.patch: New file
- Simplify-X-C1-C2.patch: New file
- gcc.spec: Add new patches
- Handle-POLY_INT_CSTs-in-declare_return_value.patch: New file
- Handle-POLY_INT_CST-in-copy_reference_ops_from_ref.patch: New file
- fix-strncpy-inline-warning.patch: New file
