Chris Lattner 7a6aa1a391 Enhance a bunch of transformations in instcombine to start generating
exact/nsw/nuw shifts and have instcombine infer them when it can prove
that the relevant properties are true for a given shift without them.

Also, a variety of refactoring to use the new patternmatch logic thrown
in for good luck.  I believe that this takes care of a bunch of related
code quality issues attached to PR8862.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125267 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-10 05:36:31 +00:00

145 lines
2.8 KiB
LLVM

; RUN: opt < %s -instcombine -S | FileCheck %s
; CHECK: @sdiv1
; CHECK: sdiv i32 %x, 8
define i32 @sdiv1(i32 %x) {
%y = sdiv i32 %x, 8
ret i32 %y
}
; CHECK: @sdiv2
; CHECK: ashr exact i32 %x, 3
define i32 @sdiv2(i32 %x) {
%y = sdiv exact i32 %x, 8
ret i32 %y
}
; CHECK: @sdiv3
; CHECK: %y = srem i32 %x, 3
; CHECK: %z = sub i32 %x, %y
; CHECK: ret i32 %z
define i32 @sdiv3(i32 %x) {
%y = sdiv i32 %x, 3
%z = mul i32 %y, 3
ret i32 %z
}
; CHECK: @sdiv4
; CHECK: ret i32 %x
define i32 @sdiv4(i32 %x) {
%y = sdiv exact i32 %x, 3
%z = mul i32 %y, 3
ret i32 %z
}
; CHECK: i32 @sdiv5
; CHECK: %y = srem i32 %x, 3
; CHECK: %z = sub i32 %y, %x
; CHECK: ret i32 %z
define i32 @sdiv5(i32 %x) {
%y = sdiv i32 %x, 3
%z = mul i32 %y, -3
ret i32 %z
}
; CHECK: @sdiv6
; CHECK: %z = sub i32 0, %x
; CHECK: ret i32 %z
define i32 @sdiv6(i32 %x) {
%y = sdiv exact i32 %x, 3
%z = mul i32 %y, -3
ret i32 %z
}
; CHECK: @udiv1
; CHECK: ret i32 %x
define i32 @udiv1(i32 %x, i32 %w) {
%y = udiv exact i32 %x, %w
%z = mul i32 %y, %w
ret i32 %z
}
; CHECK: @udiv2
; CHECK: %z = lshr exact i32 %x, %w
; CHECK: ret i32 %z
define i32 @udiv2(i32 %x, i32 %w) {
%y = shl i32 1, %w
%z = udiv exact i32 %x, %y
ret i32 %z
}
; CHECK: @ashr1
; CHECK: %B = ashr exact i64 %A, 2
; CHECK: ret i64 %B
define i64 @ashr1(i64 %X) nounwind {
%A = shl i64 %X, 8
%B = ashr i64 %A, 2 ; X/4
ret i64 %B
}
; CHECK: @ashr_icmp
; CHECK: %B = icmp eq i64 %X, 0
; CHECK: ret i1 %B
define i1 @ashr_icmp(i64 %X) nounwind {
%A = ashr exact i64 %X, 2 ; X/4
%B = icmp eq i64 %A, 0
ret i1 %B
}
; CHECK: @udiv_icmp1
; CHECK: icmp ne i64 %X, 0
define i1 @udiv_icmp1(i64 %X) nounwind {
%A = udiv exact i64 %X, 5 ; X/5
%B = icmp ne i64 %A, 0
ret i1 %B
}
; CHECK: @sdiv_icmp1
; CHECK: icmp eq i64 %X, 0
define i1 @sdiv_icmp1(i64 %X) nounwind {
%A = sdiv exact i64 %X, 5 ; X/5 == 0 --> x == 0
%B = icmp eq i64 %A, 0
ret i1 %B
}
; CHECK: @sdiv_icmp2
; CHECK: icmp eq i64 %X, 5
define i1 @sdiv_icmp2(i64 %X) nounwind {
%A = sdiv exact i64 %X, 5 ; X/5 == 1 --> x == 5
%B = icmp eq i64 %A, 1
ret i1 %B
}
; CHECK: @sdiv_icmp3
; CHECK: icmp eq i64 %X, -5
define i1 @sdiv_icmp3(i64 %X) nounwind {
%A = sdiv exact i64 %X, 5 ; X/5 == -1 --> x == -5
%B = icmp eq i64 %A, -1
ret i1 %B
}
; CHECK: @sdiv_icmp4
; CHECK: icmp eq i64 %X, 0
define i1 @sdiv_icmp4(i64 %X) nounwind {
%A = sdiv exact i64 %X, -5 ; X/-5 == 0 --> x == 0
%B = icmp eq i64 %A, 0
ret i1 %B
}
; CHECK: @sdiv_icmp5
; CHECK: icmp eq i64 %X, -5
define i1 @sdiv_icmp5(i64 %X) nounwind {
%A = sdiv exact i64 %X, -5 ; X/-5 == 1 --> x == -5
%B = icmp eq i64 %A, 1
ret i1 %B
}
; CHECK: @sdiv_icmp6
; CHECK: icmp eq i64 %X, 5
define i1 @sdiv_icmp6(i64 %X) nounwind {
%A = sdiv exact i64 %X, -5 ; X/-5 == 1 --> x == 5
%B = icmp eq i64 %A, -1
ret i1 %B
}