02b9e45a7e
The test case from: https://bugs.llvm.org/show_bug.cgi?id=42771 ...shows a ~30x slowdown caused by the awkward loop iteration (rL207302) that is seemingly done just to avoid invalidating the instruction iterator. We can instead delay instruction deletion until we reach the end of the block (or we could delay until we reach the end of all blocks). There's a test diff here for a degenerate case with llvm.assume that is not meaningful in itself, but serves to verify this change in logic. This change probably doesn't result in much overall compile-time improvement because we call '-instsimplify' as a standalone pass only once in the standard -O2 opt pipeline currently. Differential Revision: https://reviews.llvm.org/D65336 llvm-svn: 367173
94 lines
3.5 KiB
LLVM
94 lines
3.5 KiB
LLVM
; NOTE: Assertions have been autogenerated by update_test_checks.py
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; RUN: opt -instsimplify -S < %s 2>&1 -pass-remarks-analysis=.* | FileCheck %s
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; Verify that warnings are emitted for the 2nd and 3rd tests.
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; CHECK: remark: /tmp/s.c:1:13: Detected conflicting code assumptions.
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; CHECK: remark: /tmp/s.c:4:10: Detected conflicting code assumptions.
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; CHECK: remark: /tmp/s.c:5:50: Detected conflicting code assumptions.
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define void @test1() {
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; CHECK-LABEL: @test1(
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; CHECK: ret void
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;
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call void @llvm.assume(i1 1)
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ret void
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}
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; The alloca guarantees that the low bits of %a are zero because of alignment.
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; The assume says the opposite. The assume is processed last, so that's the
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; return value. There's no way to win (we can't undo transforms that happened
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; based on half-truths), so just don't crash.
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define i64 @PR31809() !dbg !7 {
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; CHECK-LABEL: @PR31809(
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; CHECK-NEXT: ret i64 3
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;
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%a = alloca i32
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%t1 = ptrtoint i32* %a to i64, !dbg !9
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%cond = icmp eq i64 %t1, 3
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call void @llvm.assume(i1 %cond)
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ret i64 %t1
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}
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; Similar to above: there's no way to know which assumption is truthful,
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; so just don't crash.
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define i8 @conflicting_assumptions(i8 %x) !dbg !10 {
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; CHECK-LABEL: @conflicting_assumptions(
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; CHECK-NEXT: [[ADD:%.*]] = add i8 [[X:%.*]], 1, !dbg !10
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; CHECK-NEXT: call void @llvm.assume(i1 false)
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; CHECK-NEXT: [[COND2:%.*]] = icmp eq i8 [[X]], 4
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; CHECK-NEXT: call void @llvm.assume(i1 [[COND2]])
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; CHECK-NEXT: ret i8 [[ADD]]
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;
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%add = add i8 %x, 1, !dbg !11
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%cond1 = icmp eq i8 %x, 3
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call void @llvm.assume(i1 %cond1)
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%cond2 = icmp eq i8 %x, 4
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call void @llvm.assume(i1 %cond2)
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ret i8 %add
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}
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; Another case of conflicting assumptions. This would crash because we'd
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; try to set more known bits than existed in the known bits struct.
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define void @PR36270(i32 %b) !dbg !13 {
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; CHECK-LABEL: @PR36270(
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; CHECK-NEXT: tail call void @llvm.assume(i1 false)
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; CHECK-NEXT: unreachable
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;
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%B7 = xor i32 -1, 2147483647
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%and1 = and i32 %b, 3
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%B12 = lshr i32 %B7, %and1, !dbg !14
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%C1 = icmp ult i32 %and1, %B12
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tail call void @llvm.assume(i1 %C1)
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%cmp2 = icmp eq i32 0, %B12
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tail call void @llvm.assume(i1 %cmp2)
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unreachable
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}
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declare void @llvm.assume(i1) nounwind
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!3, !4, !5}
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!llvm.ident = !{!6}
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!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 4.0.0 (trunk 282540) (llvm/trunk 282542)", isOptimized: true, runtimeVersion: 0, emissionKind: LineTablesOnly, enums: !2)
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!1 = !DIFile(filename: "/tmp/s.c", directory: "/tmp")
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!2 = !{}
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!3 = !{i32 2, !"Dwarf Version", i32 4}
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!4 = !{i32 2, !"Debug Info Version", i32 3}
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!5 = !{i32 1, !"PIC Level", i32 2}
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!6 = !{!"clang version 4.0.0 (trunk 282540) (llvm/trunk 282542)"}
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!7 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 1, type: !8, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: true, unit: !0, retainedNodes: !2)
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!8 = !DISubroutineType(types: !2)
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!9 = !DILocation(line: 1, column: 13, scope: !7)
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!10 = distinct !DISubprogram(name: "bar", scope: !1, file: !1, line: 3, type: !8, isLocal: false, isDefinition: true, scopeLine: 3, isOptimized: true, unit: !0, retainedNodes: !2)
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!11 = !DILocation(line: 4, column: 10, scope: !10)
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!12 = !DILocation(line: 4, column: 3, scope: !10)
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!13 = distinct !DISubprogram(name: "PR36270", scope: !1, file: !1, line: 3, type: !8, isLocal: false, isDefinition: true, scopeLine: 3, isOptimized: true, unit: !0, retainedNodes: !2)
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!14 = !DILocation(line: 5, column: 50, scope: !13)
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