660403940c
There are a number of issues with the current code for converting ule -> ult (etc) predicates for comparisons controlling finite loops: * It sets nowrap flags, which may only hold for that particular comparison, not globally. (PR60944) * It doesn't check that the RHS is invariant. (I'm not sure this can cause practical issues independently of the previous point.) * It runs before simplifications that may be more profitable. (PR54191) This patch moves the handling for this into computeExitLimitFromICmp(), because it is somewhat tightly coupled with assumptions in that code, and addresses the aforementioned issues. Fixes https://github.com/llvm/llvm-project/issues/60944. Fixes https://github.com/llvm/llvm-project/issues/54191. Differential Revision: https://reviews.llvm.org/D145510
73 lines
2.9 KiB
LLVM
73 lines
2.9 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 2
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; RUN: opt -passes=indvars -S %s | FileCheck --check-prefix=COMMON %s
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; RUN: opt -passes=indvars -scev-range-iter-threshold=1 -S %s | FileCheck --check-prefix=COMMON %s
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target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
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define i32 @test(i1 %c.0, i32 %m) {
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; COMMON-LABEL: define i32 @test
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; COMMON-SAME: (i1 [[C_0:%.*]], i32 [[M:%.*]]) {
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; COMMON-NEXT: entry:
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; COMMON-NEXT: br label [[OUTER_HEADER:%.*]]
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; COMMON: outer.header:
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; COMMON-NEXT: [[IV_1:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[IV_1_NEXT:%.*]], [[OUTER_LATCH:%.*]] ]
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; COMMON-NEXT: [[MAX_0:%.*]] = phi i32 [ 0, [[ENTRY]] ], [ [[MAX_1:%.*]], [[OUTER_LATCH]] ]
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; COMMON-NEXT: [[TMP0:%.*]] = sext i32 [[IV_1]] to i64
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; COMMON-NEXT: br label [[INNER_1:%.*]]
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; COMMON: inner.1:
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; COMMON-NEXT: [[C_1:%.*]] = icmp slt i64 0, [[TMP0]]
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; COMMON-NEXT: br i1 [[C_1]], label [[INNER_1]], label [[INNER_2_HEADER_PREHEADER:%.*]]
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; COMMON: inner.2.header.preheader:
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; COMMON-NEXT: br label [[INNER_2_HEADER:%.*]]
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; COMMON: inner.2.header:
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; COMMON-NEXT: [[IV_3:%.*]] = phi i32 [ [[IV_3_NEXT:%.*]], [[INNER_2_LATCH:%.*]] ], [ 0, [[INNER_2_HEADER_PREHEADER]] ]
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; COMMON-NEXT: br i1 [[C_0]], label [[OUTER_LATCH]], label [[INNER_2_LATCH]]
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; COMMON: inner.2.latch:
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; COMMON-NEXT: [[IV_3_NEXT]] = add i32 [[IV_3]], 1
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; COMMON-NEXT: [[C_2:%.*]] = icmp ugt i32 [[IV_3]], [[IV_1]]
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; COMMON-NEXT: br i1 [[C_2]], label [[OUTER_LATCH]], label [[INNER_2_HEADER]]
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; COMMON: outer.latch:
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; COMMON-NEXT: [[MAX_1]] = phi i32 [ [[M]], [[INNER_2_LATCH]] ], [ 0, [[INNER_2_HEADER]] ]
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; COMMON-NEXT: [[IV_1_NEXT]] = add i32 [[IV_1]], 1
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; COMMON-NEXT: [[C_3:%.*]] = icmp ugt i32 [[IV_1]], [[MAX_0]]
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; COMMON-NEXT: br i1 [[C_3]], label [[EXIT:%.*]], label [[OUTER_HEADER]], !llvm.loop [[LOOP0:![0-9]+]]
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; COMMON: exit:
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; COMMON-NEXT: ret i32 0
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;
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entry:
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br label %outer.header
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outer.header:
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%iv.1 = phi i32 [ 0, %entry ], [ %iv.1.next, %outer.latch ]
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%iv.2 = phi i32 [ 0, %entry ], [ %iv.2.next , %outer.latch ]
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%max.0 = phi i32 [ 0, %entry ], [ %max.1, %outer.latch ]
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%0 = sext i32 %iv.1 to i64
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br label %inner.1
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inner.1:
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%c.1 = icmp slt i64 0, %0
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br i1 %c.1, label %inner.1, label %inner.2.header
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inner.2.header:
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%iv.3 = phi i32 [ 0, %inner.1 ], [ %iv.3.next, %inner.2.latch ]
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br i1 %c.0, label %outer.latch, label %inner.2.latch
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inner.2.latch:
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%iv.3.next = add i32 %iv.3, 1
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%c.2 = icmp ugt i32 %iv.3, %iv.2
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br i1 %c.2, label %outer.latch, label %inner.2.header
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outer.latch:
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%max.1 = phi i32 [ %m, %inner.2.latch ], [ %iv.3, %inner.2.header ]
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%iv.1.next = add i32 %iv.1, 1
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%iv.2.next = add i32 %iv.2, 1
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%c.3 = icmp ugt i32 %iv.2, %max.0
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br i1 %c.3, label %exit, label %outer.header, !llvm.loop !0
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exit:
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ret i32 0
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}
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!0 = distinct !{!0, !1}
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!1 = !{!"llvm.loop.mustprogress"}
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