llvm-project/llvm/test/Analysis/ValueTracking/shift-recurrence-knownbits.ll

155 lines
4.1 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -instcombine -S | FileCheck %s
define i64 @test_lshr() {
; CHECK-LABEL: @test_lshr(
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: br i1 undef, label [[EXIT:%.*]], label [[LOOP]]
; CHECK: exit:
; CHECK-NEXT: ret i64 1023
;
entry:
br label %loop
loop:
%iv.lshr = phi i64 [1023, %entry], [%iv.lshr.next, %loop]
%iv.lshr.next = lshr i64 %iv.lshr, 1
br i1 undef, label %exit, label %loop
exit:
%res = or i64 %iv.lshr, 1023
ret i64 %res
}
define i64 @test_ashr_zeros() {
; CHECK-LABEL: @test_ashr_zeros(
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: br i1 undef, label [[EXIT:%.*]], label [[LOOP]]
; CHECK: exit:
; CHECK-NEXT: ret i64 1023
;
entry:
br label %loop
loop:
%iv.ashr = phi i64 [1023, %entry], [%iv.ashr.next, %loop]
%iv.ashr.next = ashr i64 %iv.ashr, 1
br i1 undef, label %exit, label %loop
exit:
%res = or i64 %iv.ashr, 1023
ret i64 %res
}
define i64 @test_ashr_ones() {
; CHECK-LABEL: @test_ashr_ones(
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: br i1 undef, label [[EXIT:%.*]], label [[LOOP]]
; CHECK: exit:
; CHECK-NEXT: ret i64 -1
;
entry:
br label %loop
loop:
%iv.ashr = phi i64 [-1023, %entry], [%iv.ashr.next, %loop]
%iv.ashr.next = ashr i64 %iv.ashr, 1
br i1 undef, label %exit, label %loop
exit:
%res = or i64 %iv.ashr, 1023
ret i64 %res
}
; Same as previous, but swapped operands to phi
define i64 @test_ashr_ones2() {
; CHECK-LABEL: @test_ashr_ones2(
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: br i1 undef, label [[EXIT:%.*]], label [[LOOP]]
; CHECK: exit:
; CHECK-NEXT: ret i64 -1
;
entry:
br label %loop
loop:
%iv.ashr = phi i64 [%iv.ashr.next, %loop], [-1023, %entry]
%iv.ashr.next = ashr i64 %iv.ashr, 1
br i1 undef, label %exit, label %loop
exit:
%res = or i64 %iv.ashr, 1023
ret i64 %res
}
; negative case for when start is unknown
define i64 @test_ashr_unknown(i64 %start) {
; CHECK-LABEL: @test_ashr_unknown(
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[IV_ASHR:%.*]] = phi i64 [ [[START:%.*]], [[ENTRY:%.*]] ], [ [[IV_ASHR_NEXT:%.*]], [[LOOP]] ]
; CHECK-NEXT: [[IV_ASHR_NEXT]] = ashr i64 [[IV_ASHR]], 1
; CHECK-NEXT: br i1 undef, label [[EXIT:%.*]], label [[LOOP]]
; CHECK: exit:
; CHECK-NEXT: [[RES:%.*]] = or i64 [[IV_ASHR]], 1023
; CHECK-NEXT: ret i64 [[RES]]
;
entry:
br label %loop
loop:
%iv.ashr = phi i64 [%start, %entry], [%iv.ashr.next, %loop]
%iv.ashr.next = ashr i64 %iv.ashr, 1
br i1 undef, label %exit, label %loop
exit:
%res = or i64 %iv.ashr, 1023
ret i64 %res
}
; Negative case where we don't have a (shift) recurrence because the operands
; of the ashr are swapped. (This does end up being a divide recurrence.)
define i64 @test_ashr_wrong_op(i64 %start) {
; CHECK-LABEL: @test_ashr_wrong_op(
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[IV_ASHR:%.*]] = phi i64 [ [[START:%.*]], [[ENTRY:%.*]] ], [ [[IV_ASHR_NEXT:%.*]], [[LOOP]] ]
; CHECK-NEXT: [[IV_ASHR_NEXT]] = lshr i64 1, [[IV_ASHR]]
; CHECK-NEXT: br i1 undef, label [[EXIT:%.*]], label [[LOOP]]
; CHECK: exit:
; CHECK-NEXT: [[RES:%.*]] = or i64 [[IV_ASHR]], 1023
; CHECK-NEXT: ret i64 [[RES]]
;
entry:
br label %loop
loop:
%iv.ashr = phi i64 [%start, %entry], [%iv.ashr.next, %loop]
%iv.ashr.next = ashr i64 1, %iv.ashr
br i1 undef, label %exit, label %loop
exit:
%res = or i64 %iv.ashr, 1023
ret i64 %res
}
define i64 @test_shl() {
; CHECK-LABEL: @test_shl(
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: br i1 undef, label [[EXIT:%.*]], label [[LOOP]]
; CHECK: exit:
; CHECK-NEXT: ret i64 0
;
entry:
br label %loop
loop:
%iv.shl = phi i64 [8, %entry], [%iv.shl.next, %loop]
%iv.shl.next = shl i64 %iv.shl, 1
br i1 undef, label %exit, label %loop
exit:
%res = and i64 %iv.shl, 7
ret i64 %res
}