2071ea24a2
We cannot infer more information from backedges in `solveBlockValueNonLocal`. However, since DT is unavailable in LVI, there is not a precise way to check whether a BB edge is a backedge. This patch only skips self loops to unblock the range analysis. The motivating case is extracted from https://github.com/llvm/llvm-project/pull/127663. Compile-time impact is high: https://llvm-compile-time-tracker.com/compare.php?from=84ddda58c870681dd12ed765e9d59d5e00567f94&to=af032f1351358f2f5b5d9f4e87c5601c23b9bd37&stat=instructions:u
40 lines
1.4 KiB
LLVM
40 lines
1.4 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
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; RUN: opt -passes=correlated-propagation -S %s | FileCheck %s
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define i64 @test_self_loop(i64 %x, i1 %cond) {
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; CHECK-LABEL: define range(i64 0, 576460752303423488) i64 @test_self_loop(
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; CHECK-SAME: i64 [[X:%.*]], i1 [[COND:%.*]]) {
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; CHECK-NEXT: [[ENTRY:.*]]:
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; CHECK-NEXT: [[COND1:%.*]] = icmp ugt i64 [[X]], 576460752303423487
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; CHECK-NEXT: br i1 [[COND1]], label %[[COMMON_RET:.*]], label %[[LOOP:.*]]
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; CHECK: [[LOOP]]:
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; CHECK-NEXT: br i1 [[COND]], label %[[INDIRECT:.*]], label %[[LOOP]]
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; CHECK: [[INDIRECT]]:
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; CHECK-NEXT: [[COND2:%.*]] = icmp eq i64 [[X]], 0
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; CHECK-NEXT: br i1 [[COND2]], label %[[COMMON_RET]], label %[[EXIT:.*]]
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; CHECK: [[EXIT]]:
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; CHECK-NEXT: br label %[[COMMON_RET]]
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; CHECK: [[COMMON_RET]]:
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; CHECK-NEXT: [[RES:%.*]] = phi i64 [ [[X]], %[[EXIT]] ], [ 0, %[[INDIRECT]] ], [ 0, %[[ENTRY]] ]
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; CHECK-NEXT: ret i64 [[RES]]
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;
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entry:
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%cond1 = icmp ugt i64 %x, 576460752303423487
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br i1 %cond1, label %common.ret, label %loop
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loop:
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br i1 %cond, label %indirect, label %loop
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indirect:
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%cond2 = icmp eq i64 %x, 0
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br i1 %cond2, label %common.ret, label %exit
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exit:
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%smax = tail call i64 @llvm.smax.i64(i64 %x, i64 1)
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br label %common.ret
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common.ret:
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%res = phi i64 [ %smax, %exit ], [ 0, %indirect ], [ 0, %entry ]
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ret i64 %res
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}
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