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llvm-project/llvm/test/Transforms/IndVarSimplify/pr38674.ll

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Revert "Temporarily Revert "Add basic loop fusion pass."" The reversion apparently deleted the test/Transforms directory. Will be re-reverting again. llvm-svn: 358552
2019-04-17 12:52:47 +08:00
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
[LoopPred] Selectively disable to preserve test cases I'm about to enable the new loop predication transform by default. It has the effect of completely destroying many read only loops - which happen to be a super common idiom in our test cases. So as to preserve test coverage of other transforms, disable the new transform where it would cause sharp test coverage regressions. (This is semantically part of the enabling commit. It's committed separate to ease revert if the actual flag flip gets reverted.)
2019-11-07 07:16:43 +08:00
; RUN: opt -S -indvars -indvars-predicate-loops=0 < %s | FileCheck %s
Revert "Temporarily Revert "Add basic loop fusion pass."" The reversion apparently deleted the test/Transforms directory. Will be re-reverting again. llvm-svn: 358552
2019-04-17 12:52:47 +08:00
; Check that we don't reuse %zext instead of %inc11 for LCSSA Phi node. Case
; with constants SCEV.
define i32 @test_01() {
; CHECK-LABEL: @test_01(
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[FOR_COND1_PREHEADER:%.*]]
; CHECK: for.cond1.preheader:
; CHECK-NEXT: br label [[FOR_COND4_PREHEADER:%.*]]
; CHECK: for.cond4.preheader:
; CHECK-NEXT: [[ZEXT:%.*]] = zext i16 1 to i32
; CHECK-NEXT: br label [[FOR_BODY6:%.*]]
; CHECK: for.cond4:
[IndVars] Eliminate loop exits with equivalent exit counts We can end up with two loop exits whose exit counts are equivalent, but whose textual representation is different and non-obvious. For the sub-case where we have a series of exits which dominate one another (common), eliminate any exits which would iterate *after* a previous exit on the exiting iteration. As noted in the TODO being removed, I'd always thought this was a good idea, but I've now seen this in a real workload as well. Interestingly, in review, Nikita pointed out there's let another oppurtunity to leverage SCEV's reasoning. If we kept track of the min of dominanting exits so far, we could discharge exits with EC >= MDE. This is less powerful than the existing transform (since later exits aren't considered), but potentially more powerful for any case where SCEV can prove a >= b, but neither a == b or a > b. I don't have an example to illustrate that oppurtunity, but won't be suprised if we find one and return to handle that case as well. Differential Revision: https://reviews.llvm.org/D69009 llvm-svn: 375379
2019-10-21 07:38:02 +08:00
; CHECK-NEXT: br i1 true, label [[FOR_BODY6]], label [[FOR_END:%.*]]
Revert "Temporarily Revert "Add basic loop fusion pass."" The reversion apparently deleted the test/Transforms directory. Will be re-reverting again. llvm-svn: 358552
2019-04-17 12:52:47 +08:00
; CHECK: for.body6:
[IndVars] Eliminate loop exits with equivalent exit counts We can end up with two loop exits whose exit counts are equivalent, but whose textual representation is different and non-obvious. For the sub-case where we have a series of exits which dominate one another (common), eliminate any exits which would iterate *after* a previous exit on the exiting iteration. As noted in the TODO being removed, I'd always thought this was a good idea, but I've now seen this in a real workload as well. Interestingly, in review, Nikita pointed out there's let another oppurtunity to leverage SCEV's reasoning. If we kept track of the min of dominanting exits so far, we could discharge exits with EC >= MDE. This is less powerful than the existing transform (since later exits aren't considered), but potentially more powerful for any case where SCEV can prove a >= b, but neither a == b or a > b. I don't have an example to illustrate that oppurtunity, but won't be suprised if we find one and return to handle that case as well. Differential Revision: https://reviews.llvm.org/D69009 llvm-svn: 375379
2019-10-21 07:38:02 +08:00
; CHECK-NEXT: [[IV:%.*]] = phi i32 [ 0, [[FOR_COND4_PREHEADER]] ], [ [[INC:%.*]], [[FOR_COND4:%.*]] ]
Revert "Temporarily Revert "Add basic loop fusion pass."" The reversion apparently deleted the test/Transforms directory. Will be re-reverting again. llvm-svn: 358552
2019-04-17 12:52:47 +08:00
; CHECK-NEXT: [[TMP0:%.*]] = icmp eq i32 [[IV]], [[ZEXT]]
; CHECK-NEXT: [[INC]] = add nuw nsw i32 [[IV]], 1
; CHECK-NEXT: br i1 [[TMP0]], label [[RETURN_LOOPEXIT:%.*]], label [[FOR_COND4]]
; CHECK: for.end:
; CHECK-NEXT: br i1 false, label [[FOR_COND4_PREHEADER]], label [[FOR_END9:%.*]]
; CHECK: for.end9:
; CHECK-NEXT: br i1 false, label [[FOR_COND1_PREHEADER]], label [[RETURN_LOOPEXIT3:%.*]]
; CHECK: return.loopexit:
; CHECK-NEXT: unreachable
; CHECK: return.loopexit3:
; CHECK-NEXT: br label [[RETURN:%.*]]
; CHECK: return:
; CHECK-NEXT: ret i32 1
;
entry:
br label %for.cond1.preheader
for.cond1.preheader: ; preds = %for.end9, %entry
br label %for.cond4.preheader
for.cond4.preheader: ; preds = %for.end, %for.cond1.preheader
%zext = zext i16 1 to i32
br label %for.body6
for.cond4: ; preds = %for.body6
%cmp5 = icmp ult i32 %inc, 2
br i1 %cmp5, label %for.body6, label %for.end
for.body6: ; preds = %for.cond4, %for.cond4.preheader
%iv = phi i32 [ 0, %for.cond4.preheader ], [ %inc, %for.cond4 ]
%0 = icmp eq i32 %iv, %zext
%inc = add nuw nsw i32 %iv, 1
br i1 %0, label %return.loopexit, label %for.cond4
for.end: ; preds = %for.cond4
br i1 false, label %for.cond4.preheader, label %for.end9
for.end9: ; preds = %for.end
%inc11 = add nuw nsw i32 0, 1
br i1 false, label %for.cond1.preheader, label %return.loopexit3
return.loopexit: ; preds = %for.body6
unreachable
return.loopexit3: ; preds = %for.end9
%inc11.lcssa = phi i32 [ %inc11, %for.end9 ]
br label %return
return: ; preds = %return.loopexit3
ret i32 %inc11.lcssa
}
; Same as test_01, but the instructions with the same SCEV have a non-constant
; SCEV.
define i32 @test_02(i32 %x) {
; CHECK-LABEL: @test_02(
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[FOR_COND1_PREHEADER:%.*]]
; CHECK: for.cond1.preheader:
; CHECK-NEXT: br label [[FOR_COND4_PREHEADER:%.*]]
; CHECK: for.cond4.preheader:
; CHECK-NEXT: [[ZEXT:%.*]] = mul i32 [[X:%.*]], 1
; CHECK-NEXT: br label [[FOR_BODY6:%.*]]
; CHECK: for.cond4:
; CHECK-NEXT: [[CMP5:%.*]] = icmp ult i32 [[INC:%.*]], 2
; CHECK-NEXT: br i1 [[CMP5]], label [[FOR_BODY6]], label [[FOR_END:%.*]]
; CHECK: for.body6:
; CHECK-NEXT: [[IV:%.*]] = phi i32 [ 0, [[FOR_COND4_PREHEADER]] ], [ [[INC]], [[FOR_COND4:%.*]] ]
; CHECK-NEXT: [[TMP0:%.*]] = icmp eq i32 [[IV]], [[ZEXT]]
; CHECK-NEXT: [[INC]] = add nuw nsw i32 [[IV]], 1
; CHECK-NEXT: br i1 [[TMP0]], label [[RETURN_LOOPEXIT:%.*]], label [[FOR_COND4]]
; CHECK: for.end:
; CHECK-NEXT: br i1 false, label [[FOR_COND4_PREHEADER]], label [[FOR_END9:%.*]]
; CHECK: for.end9:
; CHECK-NEXT: br i1 false, label [[FOR_COND1_PREHEADER]], label [[RETURN_LOOPEXIT3:%.*]]
; CHECK: return.loopexit:
; CHECK-NEXT: unreachable
; CHECK: return.loopexit3:
; CHECK-NEXT: br label [[RETURN:%.*]]
; CHECK: return:
[IndVars, RLEV] Support rewriting exit values in loops without known exits (prep work) This is a prepatory patch for future work on support exit value rewriting in loops with a mixture of computable and non-computable exit counts. The intention is to be "mostly NFC" - i.e. not enable any interesting new transforms - but in practice, there are some small output changes. The test differences are caused by cases wherewhere getSCEVAtScope can simplify a single entry phi without needing any knowledge of the loop. llvm-svn: 367485
2019-08-01 05:15:21 +08:00
; CHECK-NEXT: ret i32 [[X]]
Revert "Temporarily Revert "Add basic loop fusion pass."" The reversion apparently deleted the test/Transforms directory. Will be re-reverting again. llvm-svn: 358552
2019-04-17 12:52:47 +08:00
;
entry:
br label %for.cond1.preheader
for.cond1.preheader: ; preds = %for.end9, %entry
br label %for.cond4.preheader
for.cond4.preheader: ; preds = %for.end, %for.cond1.preheader
%zext = mul i32 %x, 1
br label %for.body6
for.cond4: ; preds = %for.body6
%cmp5 = icmp ult i32 %inc, 2
br i1 %cmp5, label %for.body6, label %for.end
for.body6: ; preds = %for.cond4, %for.cond4.preheader
%iv = phi i32 [ 0, %for.cond4.preheader ], [ %inc, %for.cond4 ]
%0 = icmp eq i32 %iv, %zext
%inc = add nuw nsw i32 %iv, 1
br i1 %0, label %return.loopexit, label %for.cond4
for.end: ; preds = %for.cond4
br i1 false, label %for.cond4.preheader, label %for.end9
for.end9: ; preds = %for.end
%inc11 = add nuw nsw i32 0, %x
br i1 false, label %for.cond1.preheader, label %return.loopexit3
return.loopexit: ; preds = %for.body6
unreachable
return.loopexit3: ; preds = %for.end9
%inc11.lcssa = phi i32 [ %inc11, %for.end9 ]
br label %return
return: ; preds = %return.loopexit3
ret i32 %inc11.lcssa
}