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Revision tags: llvmorg-18.1.8, llvmorg-18.1.7, llvmorg-18.1.6, llvmorg-18.1.5, llvmorg-18.1.4, llvmorg-18.1.3, llvmorg-18.1.2, llvmorg-18.1.1, llvmorg-18.1.0, llvmorg-18.1.0-rc4, llvmorg-18.1.0-rc3, llvmorg-18.1.0-rc2, llvmorg-18.1.0-rc1, llvmorg-19-init |
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| #
fbcf8a8c |
| 23-Dec-2023 |
Florian Hahn <flo@fhahn.com> |
[ConstraintElim] Add (UGE, var, 0) to unsigned system for new vars. (#76262)
The constraint system used for ConstraintElimination assumes all
varibles to be signed. This can cause missed optimizati
[ConstraintElim] Add (UGE, var, 0) to unsigned system for new vars. (#76262)
The constraint system used for ConstraintElimination assumes all
varibles to be signed. This can cause missed optimization in the
unsigned system, due to missing the information that all variables are
unsigned (non-negative).
Variables can be marked as non-negative by adding Var >= 0 for all
variables. This is done for arguments on ConstraintInfo construction and
after adding new variables. This handles cases like the ones outlined in
https://discourse.llvm.org/t/why-does-llvm-not-perform-range-analysis-on-integer-values/74341
The original example shared above is now handled without this change,
but adding another variable means that instcombine won't be able to
simplify examples like https://godbolt.org/z/hTnra7zdY
Adding the extra variables comes with a slight compile-time increase
https://llvm-compile-time-tracker.com/compare.php?from=7568b36a2bc1a1e496ec29246966ffdfc3a8b87f&to=641a47f0acce7755e340447386013a2e086f03d9&stat=instructions:u
stage1-O3 stage1-ReleaseThinLTO stage1-ReleaseLTO-g stage1-O0-g
+0.04% +0.07% +0.05% +0.02%
stage2-O3 stage2-O0-g stage2-clang
+0.05% +0.05% +0.05%
https://github.com/llvm/llvm-project/pull/76262
show more ...
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Revision tags: llvmorg-17.0.6, llvmorg-17.0.5, llvmorg-17.0.4, llvmorg-17.0.3, llvmorg-17.0.2, llvmorg-17.0.1, llvmorg-17.0.0, llvmorg-17.0.0-rc4 |
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| #
13ffde31 |
| 24-Aug-2023 |
Florian Hahn <flo@fhahn.com> |
[ConstraintElim] Remove dead compares after simplification.
Remove compares after replacing all uses. Cleaning dead compares can
enable additional simplifications when adjusting the position of the
[ConstraintElim] Remove dead compares after simplification.
Remove compares after replacing all uses. Cleaning dead compares can
enable additional simplifications when adjusting the position of the
pass slightly. In particular, it seems like the additional dead
instructions may prevent SimplifyCFG performing some folds.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D158760
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Revision tags: llvmorg-17.0.0-rc3, llvmorg-17.0.0-rc2, llvmorg-17.0.0-rc1, llvmorg-18-init, llvmorg-16.0.6, llvmorg-16.0.5, llvmorg-16.0.4, llvmorg-16.0.3, llvmorg-16.0.2, llvmorg-16.0.1, llvmorg-16.0.0, llvmorg-16.0.0-rc4, llvmorg-16.0.0-rc3, llvmorg-16.0.0-rc2, llvmorg-16.0.0-rc1, llvmorg-17-init, llvmorg-15.0.7, llvmorg-15.0.6, llvmorg-15.0.5, llvmorg-15.0.4, llvmorg-15.0.3 |
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| #
7c1b80e3 |
| 15-Oct-2022 |
Florian Hahn <flo@fhahn.com> |
[ConstraintElim] Support unsigned decomposition of mul/shl nuw..const
Support decomposition for `mul/shl nuw` with constant operand for unsigned
queries. Those expressions should not wrap in the uns
[ConstraintElim] Support unsigned decomposition of mul/shl nuw..const
Support decomposition for `mul/shl nuw` with constant operand for unsigned
queries. Those expressions should not wrap in the unsigned sense and can
be added directly to the unsigned system.
show more ...
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| #
fb3e2bef |
| 14-Oct-2022 |
Florian Hahn <flo@fhahn.com> |
[ConstraintElim] Add test cases for shl and mul.
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