[NFC][InstCombine][InstSimplify] PR43251 - and some patterns with offset != 0

https://rise4fun.com/Alive/21b

llvm-svn: 371537
This commit is contained in:
Roman Lebedev 2019-09-10 17:13:59 +00:00
parent da027275c6
commit 880657c97c
2 changed files with 141 additions and 1 deletions

View File

@ -11,6 +11,8 @@ declare void @use1(i1)
declare {i8, i1} @llvm.usub.with.overflow(i8, i8)
declare void @useagg({i8, i1})
declare void @llvm.assume(i1)
; There is a number of base patterns..
define i1 @t0_noncanonical_ignoreme(i8 %base, i8 %offset) {
@ -371,7 +373,7 @@ define i1 @t12(i8 %base, i8 %offset) {
;
%adjusted = sub i8 %base, %offset
call void @use8(i8 %adjusted)
%underflow = icmp ugt i8 %adjusted, %base
%underflow = icmp ult i8 %base, %offset
call void @use1(i1 %underflow)
%null = icmp eq i8 %adjusted, 0
call void @use1(i1 %null)
@ -421,3 +423,57 @@ define i1 @t13(i8 %base, i8 %offset) {
%r = and i1 %null, %underflow
ret i1 %r
}
;-------------------------------------------------------------------------------
define i1 @t15(i8 %base, i8 %offset) {
; CHECK-LABEL: @t15(
; CHECK-NEXT: [[CMP:%.*]] = icmp ne i8 [[OFFSET:%.*]], 0
; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]])
; CHECK-NEXT: [[ADJUSTED:%.*]] = sub i8 [[BASE:%.*]], [[OFFSET]]
; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]])
; CHECK-NEXT: [[NO_UNDERFLOW:%.*]] = icmp ult i8 [[ADJUSTED]], [[BASE]]
; CHECK-NEXT: call void @use1(i1 [[NO_UNDERFLOW]])
; CHECK-NEXT: [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0
; CHECK-NEXT: call void @use1(i1 [[NOT_NULL]])
; CHECK-NEXT: [[R:%.*]] = and i1 [[NOT_NULL]], [[NO_UNDERFLOW]]
; CHECK-NEXT: ret i1 [[R]]
;
%cmp = icmp ne i8 %offset, 0
call void @llvm.assume(i1 %cmp)
%adjusted = sub i8 %base, %offset
call void @use8(i8 %adjusted)
%no_underflow = icmp ult i8 %adjusted, %base
call void @use1(i1 %no_underflow)
%not_null = icmp ne i8 %adjusted, 0
call void @use1(i1 %not_null)
%r = and i1 %not_null, %no_underflow
ret i1 %r
}
define i1 @t20(i8 %base, i8 %offset) {
; CHECK-LABEL: @t20(
; CHECK-NEXT: [[CMP:%.*]] = icmp ne i8 [[OFFSET:%.*]], 0
; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]])
; CHECK-NEXT: [[ADJUSTED:%.*]] = sub i8 [[BASE:%.*]], [[OFFSET]]
; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]])
; CHECK-NEXT: [[NO_UNDERFLOW:%.*]] = icmp uge i8 [[ADJUSTED]], [[BASE]]
; CHECK-NEXT: call void @use1(i1 [[NO_UNDERFLOW]])
; CHECK-NEXT: [[NOT_NULL:%.*]] = icmp eq i8 [[ADJUSTED]], 0
; CHECK-NEXT: call void @use1(i1 [[NOT_NULL]])
; CHECK-NEXT: [[R:%.*]] = or i1 [[NOT_NULL]], [[NO_UNDERFLOW]]
; CHECK-NEXT: ret i1 [[R]]
;
%cmp = icmp ne i8 %offset, 0
call void @llvm.assume(i1 %cmp)
%adjusted = sub i8 %base, %offset
call void @use8(i8 %adjusted)
%no_underflow = icmp uge i8 %adjusted, %base
call void @use1(i1 %no_underflow)
%not_null = icmp eq i8 %adjusted, 0
call void @use1(i1 %not_null)
%r = or i1 %not_null, %no_underflow
ret i1 %r
}

View File

@ -0,0 +1,84 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt %s -instsimplify -S | FileCheck %s
; Here we subtract two values, check that subtraction did not overflow AND
; that the result is non-zero. This can be simplified just to a comparison
; between the base and offset.
declare void @llvm.assume(i1)
define i1 @t0(i8 %base, i8 %offset) {
; CHECK-LABEL: @t0(
; CHECK-NEXT: [[CMP:%.*]] = icmp ne i8 [[OFFSET:%.*]], 0
; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]])
; CHECK-NEXT: [[ADJUSTED:%.*]] = sub i8 [[BASE:%.*]], [[OFFSET]]
; CHECK-NEXT: [[NO_UNDERFLOW:%.*]] = icmp uge i8 [[ADJUSTED]], [[BASE]]
; CHECK-NEXT: [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0
; CHECK-NEXT: [[R:%.*]] = and i1 [[NOT_NULL]], [[NO_UNDERFLOW]]
; CHECK-NEXT: ret i1 [[R]]
;
%cmp = icmp ne i8 %offset, 0
call void @llvm.assume(i1 %cmp)
%adjusted = sub i8 %base, %offset
%no_underflow = icmp uge i8 %adjusted, %base
%not_null = icmp ne i8 %adjusted, 0
%r = and i1 %not_null, %no_underflow
ret i1 %r
}
define i1 @t1(i8 %base, i8 %offset) {
; CHECK-LABEL: @t1(
; CHECK-NEXT: [[CMP:%.*]] = icmp ne i8 [[OFFSET:%.*]], 0
; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]])
; CHECK-NEXT: [[ADJUSTED:%.*]] = sub i8 [[BASE:%.*]], [[OFFSET]]
; CHECK-NEXT: [[NO_UNDERFLOW:%.*]] = icmp ult i8 [[ADJUSTED]], [[BASE]]
; CHECK-NEXT: [[NOT_NULL:%.*]] = icmp eq i8 [[ADJUSTED]], 0
; CHECK-NEXT: [[R:%.*]] = or i1 [[NOT_NULL]], [[NO_UNDERFLOW]]
; CHECK-NEXT: ret i1 [[R]]
;
%cmp = icmp ne i8 %offset, 0
call void @llvm.assume(i1 %cmp)
%adjusted = sub i8 %base, %offset
%no_underflow = icmp ult i8 %adjusted, %base
%not_null = icmp eq i8 %adjusted, 0
%r = or i1 %not_null, %no_underflow
ret i1 %r
}
define i1 @t2_commutative(i8 %base, i8 %offset) {
; CHECK-LABEL: @t2_commutative(
; CHECK-NEXT: [[CMP:%.*]] = icmp ne i8 [[OFFSET:%.*]], 0
; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]])
; CHECK-NEXT: [[ADJUSTED:%.*]] = sub i8 [[BASE:%.*]], [[OFFSET]]
; CHECK-NEXT: [[NO_UNDERFLOW:%.*]] = icmp ule i8 [[BASE]], [[ADJUSTED]]
; CHECK-NEXT: [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0
; CHECK-NEXT: [[R:%.*]] = and i1 [[NOT_NULL]], [[NO_UNDERFLOW]]
; CHECK-NEXT: ret i1 [[R]]
;
%cmp = icmp ne i8 %offset, 0
call void @llvm.assume(i1 %cmp)
%adjusted = sub i8 %base, %offset
%no_underflow = icmp ule i8 %base, %adjusted
%not_null = icmp ne i8 %adjusted, 0
%r = and i1 %not_null, %no_underflow
ret i1 %r
}
; We don't know that offset is non-zero, so we can't fold.
define i1 @t3_bad(i8 %base, i8 %offset) {
; CHECK-LABEL: @t3_bad(
; CHECK-NEXT: [[ADJUSTED:%.*]] = sub i8 [[BASE:%.*]], [[OFFSET:%.*]]
; CHECK-NEXT: [[NO_UNDERFLOW:%.*]] = icmp uge i8 [[ADJUSTED]], [[BASE]]
; CHECK-NEXT: [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0
; CHECK-NEXT: [[R:%.*]] = and i1 [[NOT_NULL]], [[NO_UNDERFLOW]]
; CHECK-NEXT: ret i1 [[R]]
;
%adjusted = sub i8 %base, %offset
%no_underflow = icmp uge i8 %adjusted, %base
%not_null = icmp ne i8 %adjusted, 0
%r = and i1 %not_null, %no_underflow
ret i1 %r
}