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[InstCombine] add tests for udiv-by-constant demanded bits; NFC

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Sanjay Patel
2022-12-28 11:04:02 -05:00
parent 30033bdaf3
commit 7f0c11509e
1 changed files with 68 additions and 15 deletions
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83
llvm/test/Transforms/InstCombine/udiv-simplify.ll
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@@ -83,25 +83,78 @@ define i177 @ossfuzz_4857(i177 %X, i177 %Y) {
ret i177 %B1
}
define i32 @udiv_demanded(i32 %a) {
; CHECK-LABEL: @udiv_demanded(
; CHECK-NEXT: [[U:%.*]] = udiv i32 [[A:%.*]], 12
; CHECK-NEXT: ret i32 [[U]]
; 2 low bits are not needed because 12 has 2 trailing zeros
define i8 @udiv_demanded_low_bits_set(i8 %a) {
; CHECK-LABEL: @udiv_demanded_low_bits_set(
; CHECK-NEXT: [[U:%.*]] = udiv i8 [[A:%.*]], 12
; CHECK-NEXT: ret i8 [[U]]
;
%o = or i32 %a, 3
%u = udiv i32 %o, 12
ret i32 %u
%o = or i8 %a, 3
%u = udiv i8 %o, 12
ret i8 %u
}
define i32 @udiv_exact_demanded(i32 %a) {
; CHECK-LABEL: @udiv_exact_demanded(
; CHECK-NEXT: [[O:%.*]] = and i32 [[A:%.*]], -3
; CHECK-NEXT: [[U:%.*]] = udiv exact i32 [[O]], 12
; CHECK-NEXT: ret i32 [[U]]
; TODO: This can't divide evenly, so it is poison.
define i8 @udiv_exact_demanded_low_bits_set(i8 %a) {
; CHECK-LABEL: @udiv_exact_demanded_low_bits_set(
; CHECK-NEXT: [[O:%.*]] = or i8 [[A:%.*]], 3
; CHECK-NEXT: [[U:%.*]] = udiv exact i8 [[O]], 12
; CHECK-NEXT: ret i8 [[U]]
;
%o = and i32 %a, -3
%u = udiv exact i32 %o, 12
ret i32 %u
%o = or i8 %a, 3
%u = udiv exact i8 %o, 12
ret i8 %u
}
; All high bits are set, so this simplifies.
define i8 @udiv_demanded_high_bits_set(i8 %x, i8 %y) {
; CHECK-LABEL: @udiv_demanded_high_bits_set(
; CHECK-NEXT: ret i8 21
;
%o = or i8 %x, -4
%r = udiv i8 %o, 12
ret i8 %r
}
; TODO: This should fold the same as above.
define i8 @udiv_exact_demanded_high_bits_set(i8 %x, i8 %y) {
; CHECK-LABEL: @udiv_exact_demanded_high_bits_set(
; CHECK-NEXT: [[O:%.*]] = or i8 [[X:%.*]], -4
; CHECK-NEXT: [[R:%.*]] = udiv exact i8 [[O]], 12
; CHECK-NEXT: ret i8 [[R]]
;
%o = or i8 %x, -4
%r = udiv exact i8 %o, 12
ret i8 %r
}
; 2 low bits are not needed because 12 has 2 trailing zeros
define i8 @udiv_demanded_low_bits_clear(i8 %a) {
; CHECK-LABEL: @udiv_demanded_low_bits_clear(
; CHECK-NEXT: [[U:%.*]] = udiv i8 [[A:%.*]], 12
; CHECK-NEXT: ret i8 [[U]]
;
%o = and i8 %a, -4
%u = udiv i8 %o, 12
ret i8 %u
}
; TODO: This should fold the same as above.
define i8 @udiv_exact_demanded_low_bits_clear(i8 %a) {
; CHECK-LABEL: @udiv_exact_demanded_low_bits_clear(
; CHECK-NEXT: [[O:%.*]] = and i8 [[A:%.*]], -4
; CHECK-NEXT: [[U:%.*]] = udiv exact i8 [[O]], 12
; CHECK-NEXT: ret i8 [[U]]
;
%o = and i8 %a, -4
%u = udiv exact i8 %o, 12
ret i8 %u
}
define <vscale x 1 x i32> @udiv_demanded3(<vscale x 1 x i32> %a) {