5fe146672d
An example from https://github.com/image-rs/image: ``` define void @test_ult_rhsc(i8 %x) { %val = add nsw i8 %x, -2 %cmp = icmp ult i8 %val, 11 %cond = select i1 %cmp, i8 %val, i8 6 switch i8 %cond, label %bb1 [ i8 0, label %bb2 i8 10, label %bb3 ] bb1: call void @func1() unreachable bb2: call void @func2() unreachable bb3: call void @func3() unreachable } ``` When `%cmp` evaluates to false, we can prove that the range of `%val` is [11, umax]. Thus we can safely replace `%cond` with `%val` since both `switch 6` and `switch %val` go to the default dest `%bb1`. Alive2: https://alive2.llvm.org/ce/z/uSTj6w Godbolt: https://godbolt.org/z/MGrG84bzr This patch will benefit many rust applications and some C/C++ applications (e.g., cvc5).
160 lines
3.9 KiB
LLVM
160 lines
3.9 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
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; RUN: opt < %s -passes=instcombine -S | FileCheck %s
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define void @test_ult_rhsc(i8 %x) {
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; CHECK-LABEL: define void @test_ult_rhsc(
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; CHECK-SAME: i8 [[X:%.*]]) {
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; CHECK-NEXT: switch i8 [[X]], label [[BB1:%.*]] [
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; CHECK-NEXT: i8 2, label [[BB2:%.*]]
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; CHECK-NEXT: i8 12, label [[BB3:%.*]]
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; CHECK-NEXT: ]
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; CHECK: bb1:
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; CHECK-NEXT: call void @func1()
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; CHECK-NEXT: unreachable
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; CHECK: bb2:
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; CHECK-NEXT: call void @func2()
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; CHECK-NEXT: unreachable
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; CHECK: bb3:
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; CHECK-NEXT: call void @func3()
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; CHECK-NEXT: unreachable
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;
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%val = add nsw i8 %x, -2
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%cmp = icmp ult i8 %val, 11
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%cond = select i1 %cmp, i8 %val, i8 6
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switch i8 %cond, label %bb1 [
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i8 0, label %bb2
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i8 10, label %bb3
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]
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bb1:
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call void @func1()
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unreachable
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bb2:
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call void @func2()
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unreachable
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bb3:
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call void @func3()
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unreachable
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}
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define void @test_eq_lhsc(i8 %x) {
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; CHECK-LABEL: define void @test_eq_lhsc(
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; CHECK-SAME: i8 [[X:%.*]]) {
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; CHECK-NEXT: switch i8 [[X]], label [[BB1:%.*]] [
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; CHECK-NEXT: i8 0, label [[BB2:%.*]]
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; CHECK-NEXT: i8 10, label [[BB3:%.*]]
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; CHECK-NEXT: ]
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; CHECK: bb1:
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; CHECK-NEXT: call void @func1()
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; CHECK-NEXT: unreachable
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; CHECK: bb2:
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; CHECK-NEXT: call void @func2()
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; CHECK-NEXT: unreachable
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; CHECK: bb3:
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; CHECK-NEXT: call void @func3()
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; CHECK-NEXT: unreachable
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;
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%cmp = icmp eq i8 %x, 4
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%cond = select i1 %cmp, i8 6, i8 %x
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switch i8 %cond, label %bb1 [
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i8 0, label %bb2
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i8 10, label %bb3
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]
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bb1:
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call void @func1()
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unreachable
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bb2:
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call void @func2()
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unreachable
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bb3:
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call void @func3()
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unreachable
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}
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define void @test_ult_rhsc_invalid_cond(i8 %x, i8 %y) {
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; CHECK-LABEL: define void @test_ult_rhsc_invalid_cond(
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; CHECK-SAME: i8 [[X:%.*]], i8 [[Y:%.*]]) {
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; CHECK-NEXT: [[VAL:%.*]] = add nsw i8 [[X]], -2
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; CHECK-NEXT: [[CMP:%.*]] = icmp ult i8 [[Y]], 11
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; CHECK-NEXT: [[COND:%.*]] = select i1 [[CMP]], i8 [[VAL]], i8 6
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; CHECK-NEXT: switch i8 [[COND]], label [[BB1:%.*]] [
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; CHECK-NEXT: i8 0, label [[BB2:%.*]]
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; CHECK-NEXT: i8 10, label [[BB3:%.*]]
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; CHECK-NEXT: i8 13, label [[BB3]]
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; CHECK-NEXT: ]
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; CHECK: bb1:
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; CHECK-NEXT: call void @func1()
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; CHECK-NEXT: unreachable
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; CHECK: bb2:
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; CHECK-NEXT: call void @func2()
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; CHECK-NEXT: unreachable
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; CHECK: bb3:
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; CHECK-NEXT: call void @func3()
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; CHECK-NEXT: unreachable
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;
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%val = add nsw i8 %x, -2
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%cmp = icmp ult i8 %y, 11
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%cond = select i1 %cmp, i8 %val, i8 6
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switch i8 %cond, label %bb1 [
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i8 0, label %bb2
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i8 10, label %bb3
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i8 13, label %bb3
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]
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bb1:
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call void @func1()
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unreachable
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bb2:
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call void @func2()
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unreachable
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bb3:
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call void @func3()
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unreachable
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}
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define void @test_ult_rhsc_fail(i8 %x) {
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; CHECK-LABEL: define void @test_ult_rhsc_fail(
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; CHECK-SAME: i8 [[X:%.*]]) {
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; CHECK-NEXT: [[VAL:%.*]] = add nsw i8 [[X]], -2
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; CHECK-NEXT: [[CMP:%.*]] = icmp ult i8 [[VAL]], 11
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; CHECK-NEXT: [[COND:%.*]] = select i1 [[CMP]], i8 [[VAL]], i8 6
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; CHECK-NEXT: switch i8 [[COND]], label [[BB1:%.*]] [
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; CHECK-NEXT: i8 0, label [[BB2:%.*]]
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; CHECK-NEXT: i8 10, label [[BB3:%.*]]
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; CHECK-NEXT: i8 13, label [[BB3]]
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; CHECK-NEXT: ]
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; CHECK: bb1:
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; CHECK-NEXT: call void @func1()
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; CHECK-NEXT: unreachable
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; CHECK: bb2:
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; CHECK-NEXT: call void @func2()
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; CHECK-NEXT: unreachable
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; CHECK: bb3:
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; CHECK-NEXT: call void @func3()
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; CHECK-NEXT: unreachable
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;
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%val = add nsw i8 %x, -2
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%cmp = icmp ult i8 %val, 11
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%cond = select i1 %cmp, i8 %val, i8 6
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switch i8 %cond, label %bb1 [
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i8 0, label %bb2
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i8 10, label %bb3
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i8 13, label %bb3
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]
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bb1:
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call void @func1()
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unreachable
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bb2:
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call void @func2()
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unreachable
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bb3:
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call void @func3()
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unreachable
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}
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declare void @func1()
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declare void @func2()
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declare void @func3()
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