On 11/14/25 8:09 AM, Richard Biener wrote:
The testcases from PR121744 and PR121685 fail to be optimized when
the method with the access based on 'this' is inlined. The following
adds an early loop-invariant motion pass to combat this. I have
added a knob on PHI-motion as I think this is neither wanted early
nor in the places we call LIM on-demand on a function.
I've mass-edited the testsuite to get rid of UNRESOLVEDs, extra
fails are the following, sofar not looked at in detail. I'm looking
for general comments on adding LIM early.
Bootstrapped and tested on x86_64-unknown-linux-gnu (with the following
extra FAILs).
+FAIL: c-c++-common/restrict-2.c -std=gnu++17 scan-tree-dump-times lim3 "Moving
statement" 11
+FAIL: g++.dg/tree-ssa/pr117123.C -std=gnu++17 scan-tree-dump-times optimized "if
" 3
+FAIL: gcc.dg/loop-unswitch-1.c scan-tree-dump unswitch "unswitching loop"
+FAIL: gcc.dg/tree-ssa/loop-25.c scan-tree-dump-times profile_estimate
"Disambiguating loop" 5
+XPASS: gcc.dg/tree-ssa/pr111003.c scan-tree-dump-not optimized "foo"
+FAIL: gcc.dg/tree-ssa/pr83403-2.c scan-tree-dump-times lim3 "Executing store motion
of" 10
+FAIL: gcc.dg/tree-ssa/ssa-lim-13.c scan-tree-dump-times lim3 "Moving
statement" 2
+FAIL: gcc.dg/tree-ssa/ssa-lim-19.c scan-tree-dump-times lim3 "out of loop 1" 3
+FAIL: gcc.dg/tree-ssa/ssa-lim-19.c scan-tree-dump-times lim3 "out of loop 2" 4
+FAIL: gcc.dg/tree-ssa/ssa-lim-22.c scan-tree-dump-times lim3 "out of loop 1" 3
+FAIL: gcc.dg/tree-ssa/ssa-lim-22.c scan-tree-dump-times lim3 "out of loop 3" 4
+FAIL: gcc.dg/tree-ssa/ssa-lim-3.c scan-tree-dump lim3 "Moving
statement.*global.x.*out of loop 1"
+FAIL: gcc.dg/tree-ssa/ssa-lim-7.c scan-tree-dump lim3 "Moving statement"
+FAIL: gcc.dg/vect/pr69783.c -flto -ffat-lto-objects scan-tree-dump vect "improved
number of alias checks from [0-9]* to 2"
+FAIL: gcc.dg/vect/pr69783.c scan-tree-dump vect "improved number of alias checks
from [0-9]* to 2"
+FAIL: gcc.dg/vect/slp-9.c -flto -ffat-lto-objects scan-tree-dump-times vect
"vectorized 1 loops" 1
+FAIL: gcc.dg/vect/slp-9.c scan-tree-dump-times vect "vectorized 1 loops" 1
+FAIL: gcc.dg/vect/vect-simd-17.c -flto -ffat-lto-objects scan-tree-dump vect
"vectorized 1[1-2] loops"
+FAIL: gcc.dg/vect/vect-simd-17.c scan-tree-dump vect "vectorized 1[1-2] loops"
+FAIL: gfortran.dg/vect/O3-pr49957.f -O scan-tree-dump vect "vectorized 1
loops"
+FAIL: gfortran.dg/vect/fast-math-pr37021.f90 -O scan-tree-dump vect "vectorized
2 loops"
* passes.def: Add early loop-invariant motion pass.
* tree-ssa-loop-manip.h (loop_invariant_motion_in_fun): Add flag
for PHI-motion.
* tree-ssa-loop-im.cc (pass_lim::set_pass_param): New method.
(pass_lim::early_p): New member.
(pass_lim::execute): Do not run store-motion or phi-motion early.
Exit early when there are no loops.
(loop_invariant_motion_in_fun): New flag for PHI-motion, pass down.
(compute_invariantness): Likewise, guard PHI-motion.
* gimple-loop-iterchange.cc (pass_linterchange::execute): Do
not perform PHI-motion when doing invariant motion.
* gimple-loop-jam.cc (tree_loop_unroll_and_jam): Likewise.
* c-c++-common/restrict-2.c: Scan lim3 dump instead of lim2 dump.
No strong opinions. I don't tend of think of LIM as a costly pass. So
if it's solving real problems I wouldn't object.
jeff
