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llvm-mirror/test/Transforms/InstCombine/exact.ll
Arnaud A. de Grandmaison 6b2f7add7e Teach InstCombine to work with smaller legal types in icmp (shl %v, C1), C2
It enables to work with a smaller constant, which is target friendly for those which can compare to immediates.
It also avoids inserting a shift in favor of a trunc, which can be free on some targets.

This used to work until LLVM-3.1, but regressed with the 3.2 release.

llvm-svn: 175270
2013-02-15 14:35:47 +00:00

172 lines
3.4 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
}
; PR9120
; CHECK: @ashr_icmp1
; CHECK: %B = icmp eq i64 %X, 0
; CHECK: ret i1 %B
define i1 @ashr_icmp1(i64 %X) nounwind {
%A = ashr exact i64 %X, 2 ; X/4
%B = icmp eq i64 %A, 0
ret i1 %B
}
; CHECK: @ashr_icmp2
; CHECK: %Z = icmp slt i64 %X, 16
; CHECK: ret i1 %Z
define i1 @ashr_icmp2(i64 %X) nounwind {
%Y = ashr exact i64 %X, 2 ; x / 4
%Z = icmp slt i64 %Y, 4 ; x < 16
ret i1 %Z
}
; PR9998
; Make sure we don't transform the ashr here into an sdiv
; CHECK: @pr9998
; CHECK: [[BIT:%[A-Za-z0-9.]+]] = and i32 %V, 1
; CHECK-NEXT: [[CMP:%[A-Za-z0-9.]+]] = icmp ne i32 [[BIT]], 0
; CHECK-NEXT: ret i1 [[CMP]]
define i1 @pr9998(i32 %V) nounwind {
entry:
%W = shl i32 %V, 31
%X = ashr exact i32 %W, 31
%Y = sext i32 %X to i64
%Z = icmp ugt i64 %Y, 7297771788697658747
ret i1 %Z
}
; 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
}