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llvm-project/llvm/test/Analysis/ScalarEvolution/implied-via-division.ll
Yingwei Zheng f066d7504e
[Reland][SCEV] teach isImpliedViaOperations about samesign (#133711) 
This patch relands https://github.com/llvm/llvm-project/pull/124270.
Closes https://github.com/llvm/llvm-project/issues/126409.

The root cause is that we incorrectly preserve the samesign flag after
truncating operands of an icmp:
https://alive2.llvm.org/ce/z/4NE9gS

---------

Co-authored-by: Ramkumar Ramachandra <ramkumar.ramachandra@codasip.com>
2025-04-02 18:45:33 +08:00

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; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 5
; RUN: opt < %s -disable-output -passes="print<scalar-evolution>" \
; RUN: -scalar-evolution-classify-expressions=0 2>&1 | FileCheck %s
define void @implied1(i32 %n) {
; Prove that (n s> 1) ===> (n / 2 s> 0).
; CHECK-LABEL: 'implied1'
; CHECK-NEXT: Determining loop execution counts for: @implied1
; CHECK-NEXT: Loop %header: backedge-taken count is (-1 + %n.div.2)<nsw>
; CHECK-NEXT: Loop %header: constant max backedge-taken count is i32 1073741822
; CHECK-NEXT: Loop %header: symbolic max backedge-taken count is (-1 + %n.div.2)<nsw>
; CHECK-NEXT: Loop %header: Trip multiple is 1
;
entry:
%cmp1 = icmp sgt i32 %n, 1
%n.div.2 = sdiv i32 %n, 2
call void(i1, ...) @llvm.experimental.guard(i1 %cmp1) [ "deopt"() ]
br label %header
header:
%indvar = phi i32 [ %indvar.next, %header ], [ 0, %entry ]
%indvar.next = add i32 %indvar, 1
%exitcond = icmp sgt i32 %n.div.2, %indvar.next
br i1 %exitcond, label %header, label %exit
exit:
ret void
}
define void @implied1_samesign(i32 %n) {
; Prove that (n > 1) ===> (n / 2 s> 0).
; CHECK-LABEL: 'implied1_samesign'
; CHECK-NEXT: Determining loop execution counts for: @implied1_samesign
; CHECK-NEXT: Loop %header: backedge-taken count is (-1 + %n.div.2)<nsw>
; CHECK-NEXT: Loop %header: constant max backedge-taken count is i32 1073741822
; CHECK-NEXT: Loop %header: symbolic max backedge-taken count is (-1 + %n.div.2)<nsw>
; CHECK-NEXT: Loop %header: Trip multiple is 1
;
entry:
%cmp1 = icmp samesign ugt i32 %n, 1
%n.div.2 = sdiv i32 %n, 2
call void @llvm.assume(i1 %cmp1)
br label %header
header:
%indvar = phi i32 [ %indvar.next, %header ], [ 0, %entry ]
%indvar.next = add i32 %indvar, 1
%exitcond = icmp sgt i32 %n.div.2, %indvar.next
br i1 %exitcond, label %header, label %exit
exit:
ret void
}
define void @implied1_neg(i32 %n) {
; Prove that (n s> 0) =\=> (n / 2 s> 0).
; CHECK-LABEL: 'implied1_neg'
; CHECK-NEXT: Determining loop execution counts for: @implied1_neg
; CHECK-NEXT: Loop %header: backedge-taken count is (-1 + (1 smax %n.div.2))<nsw>
; CHECK-NEXT: Loop %header: constant max backedge-taken count is i32 1073741822
; CHECK-NEXT: Loop %header: symbolic max backedge-taken count is (-1 + (1 smax %n.div.2))<nsw>
; CHECK-NEXT: Loop %header: Trip multiple is 1
;
entry:
%cmp1 = icmp sgt i32 %n, 0
%n.div.2 = sdiv i32 %n, 2
call void(i1, ...) @llvm.experimental.guard(i1 %cmp1) [ "deopt"() ]
br label %header
header:
%indvar = phi i32 [ %indvar.next, %header ], [ 0, %entry ]
%indvar.next = add i32 %indvar, 1
%exitcond = icmp sgt i32 %n.div.2, %indvar.next
br i1 %exitcond, label %header, label %exit
exit:
ret void
}
define void @implied2(i32 %n) {
; Prove that (n s>= 2) ===> (n / 2 s> 0).
; CHECK-LABEL: 'implied2'
; CHECK-NEXT: Determining loop execution counts for: @implied2
; CHECK-NEXT: Loop %header: backedge-taken count is (-1 + %n.div.2)<nsw>
; CHECK-NEXT: Loop %header: constant max backedge-taken count is i32 1073741822
; CHECK-NEXT: Loop %header: symbolic max backedge-taken count is (-1 + %n.div.2)<nsw>
; CHECK-NEXT: Loop %header: Trip multiple is 1
;
entry:
%cmp1 = icmp sge i32 %n, 2
%n.div.2 = sdiv i32 %n, 2
call void(i1, ...) @llvm.experimental.guard(i1 %cmp1) [ "deopt"() ]
br label %header
header:
%indvar = phi i32 [ %indvar.next, %header ], [ 0, %entry ]
%indvar.next = add i32 %indvar, 1
%exitcond = icmp sgt i32 %n.div.2, %indvar.next
br i1 %exitcond, label %header, label %exit
exit:
ret void
}
define void @implied2_samesign(i32 %n) {
; Prove that (n >= 2) ===> (n / 2 s> 0).
; CHECK-LABEL: 'implied2_samesign'
; CHECK-NEXT: Determining loop execution counts for: @implied2_samesign
; CHECK-NEXT: Loop %header: backedge-taken count is (-1 + (1 smax %n.div.2))<nsw>
; CHECK-NEXT: Loop %header: constant max backedge-taken count is i32 1073741822
; CHECK-NEXT: Loop %header: symbolic max backedge-taken count is (-1 + (1 smax %n.div.2))<nsw>
; CHECK-NEXT: Loop %header: Trip multiple is 1
;
entry:
%cmp1 = icmp samesign uge i32 %n, 2
%n.div.2 = sdiv i32 %n, 2
call void @llvm.assume(i1 %cmp1)
br label %header
header:
%indvar = phi i32 [ %indvar.next, %header ], [ 0, %entry ]
%indvar.next = add i32 %indvar, 1
%exitcond = icmp sgt i32 %n.div.2, %indvar.next
br i1 %exitcond, label %header, label %exit
exit:
ret void
}
define void @implied2_neg(i32 %n) {
; Prove that (n s>= 1) =\=> (n / 2 s> 0).
; CHECK-LABEL: 'implied2_neg'
; CHECK-NEXT: Determining loop execution counts for: @implied2_neg
; CHECK-NEXT: Loop %header: backedge-taken count is (-1 + (1 smax %n.div.2))<nsw>
; CHECK-NEXT: Loop %header: constant max backedge-taken count is i32 1073741822
; CHECK-NEXT: Loop %header: symbolic max backedge-taken count is (-1 + (1 smax %n.div.2))<nsw>
; CHECK-NEXT: Loop %header: Trip multiple is 1
;
entry:
%cmp1 = icmp sge i32 %n, 1
%n.div.2 = sdiv i32 %n, 2
call void(i1, ...) @llvm.experimental.guard(i1 %cmp1) [ "deopt"() ]
br label %header
header:
%indvar = phi i32 [ %indvar.next, %header ], [ 0, %entry ]
%indvar.next = add i32 %indvar, 1
%exitcond = icmp sgt i32 %n.div.2, %indvar.next
br i1 %exitcond, label %header, label %exit
exit:
ret void
}
define void @implied3(i32 %n) {
; Prove that (n s> -2) ===> (n / 2 s>= 0).
; CHECK-LABEL: 'implied3'
; CHECK-NEXT: Determining loop execution counts for: @implied3
; CHECK-NEXT: Loop %header: backedge-taken count is (1 + %n.div.2)<nsw>
; CHECK-NEXT: Loop %header: constant max backedge-taken count is i32 1073741824
; CHECK-NEXT: Loop %header: symbolic max backedge-taken count is (1 + %n.div.2)<nsw>
; CHECK-NEXT: Loop %header: Trip multiple is 1
;
entry:
%cmp1 = icmp sgt i32 %n, -2
%n.div.2 = sdiv i32 %n, 2
call void(i1, ...) @llvm.experimental.guard(i1 %cmp1) [ "deopt"() ]
br label %header
header:
%indvar = phi i32 [ %indvar.next, %header ], [ 0, %entry ]
%indvar.next = add i32 %indvar, 1
%exitcond = icmp sge i32 %n.div.2, %indvar
br i1 %exitcond, label %header, label %exit
exit:
ret void
}
define void @implied3_samesign(i32 %n) {
; Prove that (n > -2) ===> (n / 2 s>= 0).
; CHECK-LABEL: 'implied3_samesign'
; CHECK-NEXT: Determining loop execution counts for: @implied3_samesign
; CHECK-NEXT: Loop %header: backedge-taken count is (1 + %n.div.2)<nsw>
; CHECK-NEXT: Loop %header: constant max backedge-taken count is i32 1
; CHECK-NEXT: Loop %header: symbolic max backedge-taken count is (1 + %n.div.2)<nsw>
; CHECK-NEXT: Loop %header: Trip multiple is 1
;
entry:
%cmp1 = icmp samesign ugt i32 %n, -2
%n.div.2 = sdiv i32 %n, 2
call void @llvm.assume(i1 %cmp1)
br label %header
header:
%indvar = phi i32 [ %indvar.next, %header ], [ 0, %entry ]
%indvar.next = add i32 %indvar, 1
%exitcond = icmp sge i32 %n.div.2, %indvar
br i1 %exitcond, label %header, label %exit
exit:
ret void
}
define void @implied3_neg(i32 %n) {
; Prove that (n > -3) =\=> (n / 2 >= 0).
; CHECK-LABEL: 'implied3_neg'
; CHECK-NEXT: Determining loop execution counts for: @implied3_neg
; CHECK-NEXT: Loop %header: backedge-taken count is (0 smax (1 + %n.div.2)<nsw>)
; CHECK-NEXT: Loop %header: constant max backedge-taken count is i32 1073741824
; CHECK-NEXT: Loop %header: symbolic max backedge-taken count is (0 smax (1 + %n.div.2)<nsw>)
; CHECK-NEXT: Loop %header: Trip multiple is 1
;
entry:
%cmp1 = icmp sgt i32 %n, -3
%n.div.2 = sdiv i32 %n, 2
call void(i1, ...) @llvm.experimental.guard(i1 %cmp1) [ "deopt"() ]
br label %header
header:
%indvar = phi i32 [ %indvar.next, %header ], [ 0, %entry ]
%indvar.next = add i32 %indvar, 1
%exitcond = icmp sge i32 %n.div.2, %indvar
br i1 %exitcond, label %header, label %exit
exit:
ret void
}
define void @implied4(i32 %n) {
; Prove that (n s>= -1) ===> (n / 2 s>= 0).
; CHECK-LABEL: 'implied4'
; CHECK-NEXT: Determining loop execution counts for: @implied4
; CHECK-NEXT: Loop %header: backedge-taken count is (1 + %n.div.2)<nsw>
; CHECK-NEXT: Loop %header: constant max backedge-taken count is i32 1073741824
; CHECK-NEXT: Loop %header: symbolic max backedge-taken count is (1 + %n.div.2)<nsw>
; CHECK-NEXT: Loop %header: Trip multiple is 1
;
entry:
%cmp1 = icmp sge i32 %n, -1
%n.div.2 = sdiv i32 %n, 2
call void(i1, ...) @llvm.experimental.guard(i1 %cmp1) [ "deopt"() ]
br label %header
header:
%indvar = phi i32 [ %indvar.next, %header ], [ 0, %entry ]
%indvar.next = add i32 %indvar, 1
%exitcond = icmp sge i32 %n.div.2, %indvar
br i1 %exitcond, label %header, label %exit
exit:
ret void
}
define void @implied4_samesign(i32 %n) {
; Prove that (n >= -1) ===> (n / 2 s>= 0).
; CHECK-LABEL: 'implied4_samesign'
; CHECK-NEXT: Determining loop execution counts for: @implied4_samesign
; CHECK-NEXT: Loop %header: backedge-taken count is (1 + %n.div.2)<nsw>
; CHECK-NEXT: Loop %header: constant max backedge-taken count is i32 1
; CHECK-NEXT: Loop %header: symbolic max backedge-taken count is (1 + %n.div.2)<nsw>
; CHECK-NEXT: Loop %header: Trip multiple is 1
;
entry:
%cmp1 = icmp samesign uge i32 %n, -1
%n.div.2 = sdiv i32 %n, 2
call void @llvm.assume(i1 %cmp1)
br label %header
header:
%indvar = phi i32 [ %indvar.next, %header ], [ 0, %entry ]
%indvar.next = add i32 %indvar, 1
%exitcond = icmp sge i32 %n.div.2, %indvar
br i1 %exitcond, label %header, label %exit
exit:
ret void
}
define void @implied4_neg(i32 %n) {
; Prove that (n s>= -2) =\=> (n / 2 s>= 0).
; CHECK-LABEL: 'implied4_neg'
; CHECK-NEXT: Determining loop execution counts for: @implied4_neg
; CHECK-NEXT: Loop %header: backedge-taken count is (0 smax (1 + %n.div.2)<nsw>)
; CHECK-NEXT: Loop %header: constant max backedge-taken count is i32 1073741824
; CHECK-NEXT: Loop %header: symbolic max backedge-taken count is (0 smax (1 + %n.div.2)<nsw>)
; CHECK-NEXT: Loop %header: Trip multiple is 1
;
entry:
%cmp1 = icmp sge i32 %n, -2
%n.div.2 = sdiv i32 %n, 2
call void(i1, ...) @llvm.experimental.guard(i1 %cmp1) [ "deopt"() ]
br label %header
header:
%indvar = phi i32 [ %indvar.next, %header ], [ 0, %entry ]
%indvar.next = add i32 %indvar, 1
%exitcond = icmp sge i32 %n.div.2, %indvar
br i1 %exitcond, label %header, label %exit
exit:
ret void
}
define void @test_ext_01(i32 %n) nounwind {
; Prove that (n > 1) ===> (n / 2 > 0).
; CHECK-LABEL: 'test_ext_01'
; CHECK-NEXT: Determining loop execution counts for: @test_ext_01
; CHECK-NEXT: Loop %header: backedge-taken count is (-1 + (sext i32 %n.div.2 to i64))<nsw>
; CHECK-NEXT: Loop %header: constant max backedge-taken count is i64 1073741822
; CHECK-NEXT: Loop %header: symbolic max backedge-taken count is (-1 + (sext i32 %n.div.2 to i64))<nsw>
; CHECK-NEXT: Loop %header: Trip multiple is 1
;
entry:
%cmp1 = icmp sgt i32 %n, 1
%n.div.2 = sdiv i32 %n, 2
%n.div.2.ext = sext i32 %n.div.2 to i64
call void(i1, ...) @llvm.experimental.guard(i1 %cmp1) [ "deopt"() ]
br label %header
header:
%indvar = phi i64 [ %indvar.next, %header ], [ 0, %entry ]
%indvar.next = add i64 %indvar, 1
%exitcond = icmp sgt i64 %n.div.2.ext, %indvar.next
br i1 %exitcond, label %header, label %exit
exit:
ret void
}
define void @test_ext_01neg(i32 %n) nounwind {
; Prove that (n > 0) =\=> (n / 2 > 0).
; CHECK-LABEL: 'test_ext_01neg'
; CHECK-NEXT: Determining loop execution counts for: @test_ext_01neg
; CHECK-NEXT: Loop %header: backedge-taken count is (-1 + (1 smax (sext i32 %n.div.2 to i64)))<nsw>
; CHECK-NEXT: Loop %header: constant max backedge-taken count is i64 1073741822
; CHECK-NEXT: Loop %header: symbolic max backedge-taken count is (-1 + (1 smax (sext i32 %n.div.2 to i64)))<nsw>
; CHECK-NEXT: Loop %header: Trip multiple is 1
;
entry:
%cmp1 = icmp sgt i32 %n, 0
%n.div.2 = sdiv i32 %n, 2
%n.div.2.ext = sext i32 %n.div.2 to i64
call void(i1, ...) @llvm.experimental.guard(i1 %cmp1) [ "deopt"() ]
br label %header
header:
%indvar = phi i64 [ %indvar.next, %header ], [ 0, %entry ]
%indvar.next = add i64 %indvar, 1
%exitcond = icmp sgt i64 %n.div.2.ext, %indvar.next
br i1 %exitcond, label %header, label %exit
exit:
ret void
}
define void @test_ext_02(i32 %n) nounwind {
; Prove that (n >= 2) ===> (n / 2 > 0).
; CHECK-LABEL: 'test_ext_02'
; CHECK-NEXT: Determining loop execution counts for: @test_ext_02
; CHECK-NEXT: Loop %header: backedge-taken count is (-1 + (sext i32 %n.div.2 to i64))<nsw>
; CHECK-NEXT: Loop %header: constant max backedge-taken count is i64 1073741822
; CHECK-NEXT: Loop %header: symbolic max backedge-taken count is (-1 + (sext i32 %n.div.2 to i64))<nsw>
; CHECK-NEXT: Loop %header: Trip multiple is 1
;
entry:
%cmp1 = icmp sge i32 %n, 2
%n.div.2 = sdiv i32 %n, 2
%n.div.2.ext = sext i32 %n.div.2 to i64
call void(i1, ...) @llvm.experimental.guard(i1 %cmp1) [ "deopt"() ]
br label %header
header:
%indvar = phi i64 [ %indvar.next, %header ], [ 0, %entry ]
%indvar.next = add i64 %indvar, 1
%exitcond = icmp sgt i64 %n.div.2.ext, %indvar.next
br i1 %exitcond, label %header, label %exit
exit:
ret void
}
define void @test_ext_02neg(i32 %n) nounwind {
; Prove that (n >= 1) =\=> (n / 2 > 0).
; CHECK-LABEL: 'test_ext_02neg'
; CHECK-NEXT: Determining loop execution counts for: @test_ext_02neg
; CHECK-NEXT: Loop %header: backedge-taken count is (-1 + (1 smax (sext i32 %n.div.2 to i64)))<nsw>
; CHECK-NEXT: Loop %header: constant max backedge-taken count is i64 1073741822
; CHECK-NEXT: Loop %header: symbolic max backedge-taken count is (-1 + (1 smax (sext i32 %n.div.2 to i64)))<nsw>
; CHECK-NEXT: Loop %header: Trip multiple is 1
;
entry:
%cmp1 = icmp sge i32 %n, 1
%n.div.2 = sdiv i32 %n, 2
%n.div.2.ext = sext i32 %n.div.2 to i64
call void(i1, ...) @llvm.experimental.guard(i1 %cmp1) [ "deopt"() ]
br label %header
header:
%indvar = phi i64 [ %indvar.next, %header ], [ 0, %entry ]
%indvar.next = add i64 %indvar, 1
%exitcond = icmp sgt i64 %n.div.2.ext, %indvar.next
br i1 %exitcond, label %header, label %exit
exit:
ret void
}
define void @test_ext_03(i32 %n) nounwind {
; Prove that (n > -2) ===> (n / 2 >= 0).
; CHECK-LABEL: 'test_ext_03'
; CHECK-NEXT: Determining loop execution counts for: @test_ext_03
; CHECK-NEXT: Loop %header: backedge-taken count is (1 + (sext i32 %n.div.2 to i64))<nsw>
; CHECK-NEXT: Loop %header: constant max backedge-taken count is i64 1073741824
; CHECK-NEXT: Loop %header: symbolic max backedge-taken count is (1 + (sext i32 %n.div.2 to i64))<nsw>
; CHECK-NEXT: Loop %header: Trip multiple is 1
;
entry:
%cmp1 = icmp sgt i32 %n, -2
%n.div.2 = sdiv i32 %n, 2
%n.div.2.ext = sext i32 %n.div.2 to i64
call void(i1, ...) @llvm.experimental.guard(i1 %cmp1) [ "deopt"() ]
br label %header
header:
%indvar = phi i64 [ %indvar.next, %header ], [ 0, %entry ]
%indvar.next = add i64 %indvar, 1
%exitcond = icmp sge i64 %n.div.2.ext, %indvar
br i1 %exitcond, label %header, label %exit
exit:
ret void
}
define void @test_ext_03neg(i32 %n) nounwind {
; Prove that (n > -3) =\=> (n / 2 >= 0).
; CHECK-LABEL: 'test_ext_03neg'
; CHECK-NEXT: Determining loop execution counts for: @test_ext_03neg
; CHECK-NEXT: Loop %header: backedge-taken count is (0 smax (1 + (sext i32 %n.div.2 to i64))<nsw>)
; CHECK-NEXT: Loop %header: constant max backedge-taken count is i64 1073741824
; CHECK-NEXT: Loop %header: symbolic max backedge-taken count is (0 smax (1 + (sext i32 %n.div.2 to i64))<nsw>)
; CHECK-NEXT: Loop %header: Trip multiple is 1
;
entry:
%cmp1 = icmp sgt i32 %n, -3
%n.div.2 = sdiv i32 %n, 2
%n.div.2.ext = sext i32 %n.div.2 to i64
call void(i1, ...) @llvm.experimental.guard(i1 %cmp1) [ "deopt"() ]
br label %header
header:
%indvar = phi i64 [ %indvar.next, %header ], [ 0, %entry ]
%indvar.next = add i64 %indvar, 1
%exitcond = icmp sge i64 %n.div.2.ext, %indvar
br i1 %exitcond, label %header, label %exit
exit:
ret void
}
define void @test_ext_04(i32 %n) nounwind {
; Prove that (n >= -1) ===> (n / 2 >= 0).
; CHECK-LABEL: 'test_ext_04'
; CHECK-NEXT: Determining loop execution counts for: @test_ext_04
; CHECK-NEXT: Loop %header: backedge-taken count is (1 + (sext i32 %n.div.2 to i64))<nsw>
; CHECK-NEXT: Loop %header: constant max backedge-taken count is i64 1073741824
; CHECK-NEXT: Loop %header: symbolic max backedge-taken count is (1 + (sext i32 %n.div.2 to i64))<nsw>
; CHECK-NEXT: Loop %header: Trip multiple is 1
;
entry:
%cmp1 = icmp sge i32 %n, -1
%n.div.2 = sdiv i32 %n, 2
%n.div.2.ext = sext i32 %n.div.2 to i64
call void(i1, ...) @llvm.experimental.guard(i1 %cmp1) [ "deopt"() ]
br label %header
header:
%indvar = phi i64 [ %indvar.next, %header ], [ 0, %entry ]
%indvar.next = add i64 %indvar, 1
%exitcond = icmp sge i64 %n.div.2.ext, %indvar
br i1 %exitcond, label %header, label %exit
exit:
ret void
}
define void @test_ext_04neg(i32 %n) nounwind {
; Prove that (n >= -2) =\=> (n / 2 >= 0).
; CHECK-LABEL: 'test_ext_04neg'
; CHECK-NEXT: Determining loop execution counts for: @test_ext_04neg
; CHECK-NEXT: Loop %header: backedge-taken count is (0 smax (1 + (sext i32 %n.div.2 to i64))<nsw>)
; CHECK-NEXT: Loop %header: constant max backedge-taken count is i64 1073741824
; CHECK-NEXT: Loop %header: symbolic max backedge-taken count is (0 smax (1 + (sext i32 %n.div.2 to i64))<nsw>)
; CHECK-NEXT: Loop %header: Trip multiple is 1
;
entry:
%cmp1 = icmp sge i32 %n, -2
%n.div.2 = sdiv i32 %n, 2
%n.div.2.ext = sext i32 %n.div.2 to i64
call void(i1, ...) @llvm.experimental.guard(i1 %cmp1) [ "deopt"() ]
br label %header
header:
%indvar = phi i64 [ %indvar.next, %header ], [ 0, %entry ]
%indvar.next = add i64 %indvar, 1
%exitcond = icmp sge i64 %n.div.2.ext, %indvar
br i1 %exitcond, label %header, label %exit
exit:
ret void
}
define void @swapped_predicate(i32 %n) {
; Prove that (n s>= 1) ===> (0 s>= -n / 2).
; CHECK-LABEL: 'swapped_predicate'
; CHECK-NEXT: Determining loop execution counts for: @swapped_predicate
; CHECK-NEXT: Loop %header: backedge-taken count is (1 + %n.div.2)<nuw><nsw>
; CHECK-NEXT: Loop %header: constant max backedge-taken count is i32 1073741824
; CHECK-NEXT: Loop %header: symbolic max backedge-taken count is (1 + %n.div.2)<nuw><nsw>
; CHECK-NEXT: Loop %header: Trip multiple is 1
;
entry:
%cmp1 = icmp sge i32 %n, 1
%n.div.2 = sdiv i32 %n, 2
call void @llvm.assume(i1 %cmp1)
br label %header
header:
%indvar = phi i32 [ %indvar.next, %header ], [ 0, %entry ]
%indvar.next = add i32 %indvar, 1
%minus.indvar = sub nsw i32 0, %indvar
%minus.n.div.2 = sub nsw i32 0, %n.div.2
%exitcond = icmp sge i32 %minus.indvar, %minus.n.div.2
br i1 %exitcond, label %header, label %exit
exit:
ret void
}
define void @swapped_predicate_neg(i32 %n) {
; Prove that (n s>= 1) =\=> (-n / 2 s>= 0).
; CHECK-LABEL: 'swapped_predicate_neg'
; CHECK-NEXT: Determining loop execution counts for: @swapped_predicate_neg
; CHECK-NEXT: Loop %header: Unpredictable backedge-taken count.
; CHECK-NEXT: Loop %header: Unpredictable constant max backedge-taken count.
; CHECK-NEXT: Loop %header: Unpredictable symbolic max backedge-taken count.
;
entry:
%cmp1 = icmp sge i32 %n, 1
%n.div.2 = sdiv i32 %n, 2
call void @llvm.assume(i1 %cmp1)
br label %header
header:
%indvar = phi i32 [ %indvar.next, %header ], [ 0, %entry ]
%indvar.next = add i32 %indvar, 1
%minus.indvar = sub nsw i32 0, %indvar
%minus.n.div.2 = sub nsw i32 0, %n.div.2
%exitcond = icmp sge i32 %minus.n.div.2, %minus.indvar
br i1 %exitcond, label %header, label %exit
exit:
ret void
}
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