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aad4ea476e
If we load from a location with range metadata, we can use information about the ranges of the loaded value for optimization purposes. This helps to remove redundant checks and canonicalize checks for other optimization passes. This particular patch checks whether a value is known to be non-zero from the range metadata. Currently, these tests are against InstCombine. In theory, all of these should be InstSimplify since we're not inserting any new instructions. Moving the code may follow in a separate change. Reviewed by: Hal Differential Revision: http://reviews.llvm.org/D5947 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220925 91177308-0d34-0410-b5e6-96231b3b80d8
62 lines
1.6 KiB
LLVM
62 lines
1.6 KiB
LLVM
; RUN: opt < %s -instcombine -S | FileCheck %s
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; These should be InstSimplify checks, but most of the code
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; is currently only in InstCombine. TODO: move supporting code
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; Definitely out of range
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define i1 @test_nonzero(i32* nocapture readonly %arg) {
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; CHECK-LABEL:test_nonzero
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; CHECK: ret i1 true
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%val = load i32* %arg, !range !0
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%rval = icmp ne i32 %val, 0
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ret i1 %rval
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}
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define i1 @test_nonzero2(i32* nocapture readonly %arg) {
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; CHECK-LABEL:test_nonzero2
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; CHECK: ret i1 false
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%val = load i32* %arg, !range !0
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%rval = icmp eq i32 %val, 0
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ret i1 %rval
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}
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; Potentially in range
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define i1 @test_nonzero3(i32* nocapture readonly %arg) {
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; CHECK-LABEL: test_nonzero3
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; Check that this does not trigger - it wouldn't be legal
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; CHECK: icmp
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%val = load i32* %arg, !range !1
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%rval = icmp ne i32 %val, 0
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ret i1 %rval
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}
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; Definitely in range
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define i1 @test_nonzero4(i8* nocapture readonly %arg) {
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; CHECK-LABEL: test_nonzero4
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; CHECK: ret i1 false
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%val = load i8* %arg, !range !2
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%rval = icmp ne i8 %val, 0
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ret i1 %rval
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}
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define i1 @test_nonzero5(i8* nocapture readonly %arg) {
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; CHECK-LABEL: test_nonzero5
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; CHECK: ret i1 false
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%val = load i8* %arg, !range !2
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%rval = icmp ugt i8 %val, 0
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ret i1 %rval
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}
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; Cheaper checks (most values in range meet requirements)
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define i1 @test_nonzero6(i8* %argw) {
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; CHECK-LABEL: test_nonzero6
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; CHECK: icmp ne i8 %val, 0
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%val = load i8* %argw, !range !3
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%rval = icmp sgt i8 %val, 0
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ret i1 %rval
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}
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!0 = metadata !{i32 1, i32 6}
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!1 = metadata !{i32 0, i32 6}
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!2 = metadata !{i8 0, i8 1}
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!3 = metadata !{i8 0, i8 6}
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