452714f8f8
This is analogous to D86156 (which preserves "lossy" BFI in loop passes). Lossy means that the analysis preserved may not be up to date with regards to new blocks that are added in loop passes, but BPI will not contain stale pointers to basic blocks that are deleted by the loop passes. This is achieved through BasicBlockCallbackVH in BPI, which calls eraseBlock that updates the data structures in BPI whenever a basic block is deleted. This patch does not have any changes in the upstream pipeline, since none of the loop passes in the pipeline use BPI currently. However, since BPI wasn't previously preserved in loop passes, the loop predication pass was invoking BPI *on the entire function* every time it ran in an LPM. This caused massive compile time in our downstream LPM invocation which contained loop predication. See updated test with an invocation of a loop-pipeline containing loop predication and -debug-pass turned ON. Reviewed-By: asbirlea, modimo Differential Revision: https://reviews.llvm.org/D110438
61 lines
2.5 KiB
LLVM
61 lines
2.5 KiB
LLVM
; RUN: opt -mtriple=x86_64 -passes='loop-mssa(loop-predication,licm,simple-loop-unswitch<nontrivial>,loop-simplifycfg)' -debug-pass-manager -debug-only=branch-prob -S < %s 2>&1 | FileCheck %s
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; REQUIRES: asserts
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; This test is to solely check that we do not run BPI every single time loop
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; predication is invoked (since BPI is preserved as part of
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; LoopStandardAnalysisResults).
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declare void @llvm.experimental.guard(i1, ...)
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; CHECK: Running pass: LoopPredicationPass on Loop at depth 1
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; CHECK-NEXT: Running pass: LICMPass on Loop at depth 1
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; CHECK-NEXT: Running pass: SimpleLoopUnswitchPass on Loop at depth 1
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; CHECK-NEXT: Running pass: LoopPredicationPass on Loop at depth 1
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; CHECK-NEXT: Running pass: LICMPass on Loop at depth 1
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; CHECK-NEXT: Running pass: SimpleLoopUnswitchPass on Loop at depth 1
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; CHECK-NEXT: Running pass: LoopSimplifyCFGPass on Loop at depth 1
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define i32 @unsigned_loop_0_to_n_ult_check(i32* %array, i32 %length, i32 %n) {
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entry:
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%tmp5 = icmp eq i32 %n, 0
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br i1 %tmp5, label %exit, label %loop.preheader
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loop.preheader: ; preds = %entry
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br label %loop
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loop: ; preds = %guarded, %loop.preheader
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%loop.acc = phi i32 [ %loop.acc.next, %guarded ], [ 0, %loop.preheader ]
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%i = phi i32 [ %i.next, %guarded ], [ 0, %loop.preheader ]
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%within.bounds = icmp ult i32 %i, %length
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%widenable_cond = call i1 @llvm.experimental.widenable.condition()
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%exiplicit_guard_cond = and i1 %within.bounds, %widenable_cond
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br i1 %exiplicit_guard_cond, label %guarded, label %deopt, !prof !0
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deopt: ; preds = %loop
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%deoptcall = call i32 (...) @llvm.experimental.deoptimize.i32(i32 9) [ "deopt"() ]
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ret i32 %deoptcall
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guarded: ; preds = %loop
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%i.i64 = zext i32 %i to i64
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%array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64
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%array.i = load i32, i32* %array.i.ptr, align 4
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%loop.acc.next = add i32 %loop.acc, %array.i
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%i.next = add nuw i32 %i, 1
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%continue = icmp ult i32 %i.next, %n
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br i1 %continue, label %loop, label %exit, !prof !2
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exit: ; preds = %guarded, %entry
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%result = phi i32 [ 0, %entry ], [ %loop.acc.next, %guarded ]
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ret i32 %result
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}
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declare i32 @llvm.experimental.deoptimize.i32(...)
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declare i1 @llvm.experimental.widenable.condition() #0
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attributes #0 = { inaccessiblememonly nounwind }
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!0 = !{!"branch_weights", i32 1048576, i32 1}
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!1 = !{i32 1, i32 -2147483648}
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!2 = !{!"branch_weights", i32 1024, i32 1}
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