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llvm-project/llvm/test/Transforms/InstSimplify
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Nikita Popov 5a2265647e Reapply [InstSimplify] Remove known bits constant folding 
No changes relative to last time, but after a mitigation for
an AMDGPU regression landed.

---

If SimplifyInstruction() does not succeed in simplifying the
instruction, it will compute the known bits of the instruction
in the hope that all bits are known and the instruction can be
folded to a constant. I have removed a similar optimization
from InstCombine in D75801, and would like to drop this one as well.

On average, we spend ~1% of total compile-time performing this
known bits calculation. However, if we introduce some additional
statistics for known bits computations and how many of them succeed
in simplifying the instruction we get (on test-suite):

    instsimplify.NumKnownBits: 216
    instsimplify.NumKnownBitsComputed: 13828375
    valuetracking.NumKnownBitsComputed: 45860806

Out of ~14M known bits calculations (accounting for approximately
one third of all known bits calculations), only 0.0015% succeed in
producing a constant. Those cases where we do succeed to compute
all known bits will get folded by other passes like InstCombine
later. On test-suite, only lencod.test and GCC-C-execute-pr44858.test
show a hash difference after this change. On lencod we see an
improvement (a loop phi is optimized away), on the GCC torture
test a regression (a function return value is determined only
after IPSCCP, preventing propagation from a noinline function.)

There are various regressions in InstSimplify tests. However, all
of these cases are already handled by InstCombine, and corresponding
tests have already been added there.

Differential Revision: https://reviews.llvm.org/D79294
 		2020-05-08 10:24:53 +02:00
..
2010-12-20-Boolean.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
2011-01-14-Thread.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
2011-02-01-Vector.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
2011-09-05-InsertExtractValue.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
2011-10-27-BinOpCrash.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
2011-11-23-MaskedBitsCrash.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
2013-04-19-ConstantFoldingCrash.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
AndOrXor.ll [InstSimplify] add tests for logic-of-icmp with min/max constant; NFC 2020-04-19 08:24:38 -04:00
add-mask.ll [ValueTracking] Add computeKnownBits DemandedElts support to masked add instructions (PR36319) 2020-03-18 21:50:56 +00:00
add.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
addsub.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
and-icmps-same-ops.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
and-or-icmp-min-max.ll [InstSimplify] fold and/or of compares with equality to min/max constant 2020-04-23 09:16:10 -04:00
and-or-icmp-nullptr.ll [InstSimplify] fold and/or of compares with equality to min/max constant 2020-04-23 09:16:10 -04:00
and-or-icmp-zero.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
assume-non-zero.ll [ValueTracking] isKnownNonZero() should take non-null-ness assumptions into consideration (PR43267) 2019-12-20 01:47:57 +03:00
bitcast-vector-fold.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
bitreverse-fold.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
bitreverse.ll [ValueTracking] Add computeKnownBits DemandedElts support to EXTRACTELEMENT/OR/BSWAP/BITREVERSE instructions (PR36319) 2020-03-18 18:49:58 +00:00
bswap.ll [ValueTracking] Add computeKnownBits DemandedElts support to EXTRACTELEMENT/OR/BSWAP/BITREVERSE instructions (PR36319) 2020-03-18 18:49:58 +00:00
call.ll Reapply [InstSimplify] Remove known bits constant folding 2020-05-08 10:24:53 +02:00
cast-unsigned-icmp-cmp-0.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
cast.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
cmp_of_min_max.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
compare.ll [InstSimplify] Regenerate compares tests to fix issue reported on D77354 2020-04-03 17:34:56 +01:00
constantfold-add-nuw-allones-to-allones.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
constantfold-shl-nuw-C-to-C.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
constfold-constrained.ll [FEnv] Constfold some unary constrained operations 2020-03-28 12:28:33 +07:00
dead-code-removal.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
div-by-0-guard-before-smul_ov-not.ll [InstSimplify] Drop leftover "division-by-zero guard" around `@llvm.umul.with.overflow` inverted overflow bit 2019-08-29 12:48:04 +00:00
div-by-0-guard-before-smul_ov.ll [InstSimplify] Drop leftover "division-by-zero guard" around `@llvm.umul.with.overflow` overflow bit 2019-08-29 12:47:50 +00:00
div-by-0-guard-before-umul_ov-not.ll [InstSimplify] Drop leftover "division-by-zero guard" around `@llvm.umul.with.overflow` inverted overflow bit 2019-08-29 12:48:04 +00:00
div-by-0-guard-before-umul_ov.ll [InstSimplify] Drop leftover "division-by-zero guard" around `@llvm.umul.with.overflow` overflow bit 2019-08-29 12:47:50 +00:00
div.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
exact-nsw-nuw.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
extract-element.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
fast-math.ll [ValueTracking] fix CannotBeNegativeZero() to disregard 'nsz' FMF 2020-05-05 16:04:59 -04:00
fcmp-select.ll [InstSimplify] use FMF to improve fcmp+select fold 2019-11-04 08:29:56 -05:00
fdiv.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
floating-point-arithmetic.ll [InstSimplify] Teach fsub -0.0, (fneg X) ==> X about unary fneg 2019-05-20 13:13:35 +00:00
floating-point-compare.ll [InstSimplify] enhance fcmp fold with never-nan operand 2019-06-09 13:48:59 +00:00
fold-intrinsics.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
fp-nan.ll [InstSimplify] simplify FP ops harder with FMF 2020-03-12 09:13:28 -04:00
fp-undef.ll [InstSimplify] simplify FP ops harder with FMF (part 2) 2020-03-12 09:53:20 -04:00
freeze.ll [ValueTracking] Let isGuaranteedNotToBeUndefOrPoison look into more constants/instructions 2020-04-25 23:29:54 +09:00
gep.ll [SVE] Update API ConstantVector::getSplat() to use ElementCount. 2020-03-12 13:22:41 -07:00
icmp-abs-nabs.ll [ValueTracking] When calculating known bits for integer abs, make sure we're looking at a negate and not just any instruction with the nsw flag set. 2019-08-07 18:28:16 +00:00
icmp-bool-constant.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
icmp-constant.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
icmp-ranges.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
implies.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
insertelement.ll [InstSimplify] allow insertelement-with-undef fold if poison-safe 2020-05-01 10:34:29 -04:00
known-never-nan.ll [ValueTracking] Add a basic version of isKnownNonInfinity and use it to detect more NoNaNs 2019-11-19 22:24:46 +01:00
known-non-zero.ll [ValueTracking] Allow context-sensitive nullness check for non-pointers 2019-12-09 15:15:52 -06:00
load-relative-32.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
load-relative.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
load.ll [ConstantFolding] Fix assertion failure on non-power-of-two vector load. 2019-06-19 10:28:48 +00:00
log-exp-intrinsic.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
log2-pow2-intrinsic.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
log10-pow10-intrinsic.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
logic-of-fcmps.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
maxmin.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
mul.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
negate.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
noalias-ptr.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
or-icmps-same-ops.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
or.ll Reapply [InstSimplify] Remove known bits constant folding 2020-05-08 10:24:53 +02:00
past-the-end.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
phi.ll [InstSimplify] add a phi test with 1 incoming value; NFC 2019-06-19 17:23:29 +00:00
pr28725.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
pr33957.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
ptr_diff.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
reassociate.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
redundant-null-check-in-uadd_with_overflow-of-nonnull-ptr.ll [InstSimplify] Pass SimplifyQuery into simplifyUnsignedRangeCheck() and use it for isKnownNonZero() 2019-09-11 15:32:46 +00:00
rem.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
remove-dead-call.ll [InstSimplify] Report "Changed" also when only deleting dead instructions 2019-08-09 07:08:25 +00:00
require-dominator.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
result-of-add-of-negative-is-non-zero-and-no-underflow.ll [NFC][InstSimplify] Add some more tests for D67498/D67502 2019-09-13 17:58:24 +00:00
result-of-usub-by-nonzero-is-non-zero-and-no-overflow.ll [InstSimplify] simplifyUnsignedRangeCheck(): handle more cases (PR43251) 2019-09-12 09:26:17 +00:00
result-of-usub-is-non-zero-and-no-overflow.ll [InstSimplify] Handle more 'A </>/>=/<= B &&/|| (A - B) !=/== 0' patterns (PR43251) 2019-09-25 22:59:41 +00:00
returned.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
round-intrinsics.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
saturating-add-sub.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
sdiv.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
select-and-cmp.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
select-implied.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
select-or-cmp.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
select.ll [InstSimplify] add test for select that should not be simplified; NFC 2020-04-14 13:57:30 -04:00
shift-128-kb.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
shift-knownbits.ll Reapply [InstSimplify] Remove known bits constant folding 2020-05-08 10:24:53 +02:00
shift.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
shr-nop.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
shr-scalar-vector-consistency.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
shufflevector.ll [InstSimplify] fold splat of inserted constant to vector constant 2019-12-15 09:32:03 -05:00
signed-div-rem.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
simplify-nested-bitcast.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
srem.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
sub.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
undef.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
vec-cmp.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
vector_gep.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
vector_ptr_bitcast.ll Revert "Temporarily Revert "Add basic loop fusion pass."" 2019-04-17 04:52:47 +00:00
vscale.ll [InstSimplify] update test; NFC 2020-05-01 10:06:56 -04:00