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llvm-mirror/test/Transforms/InstCombine/nsw.ll
Chris Lattner 6e84f48cd8 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.

llvm-svn: 125267
2011-02-10 05:36:31 +00:00

40 lines
793 B
LLVM

; RUN: opt < %s -instcombine -S | FileCheck %s
; CHECK: @sub1
; CHECK: %y = sub i32 0, %x
; CHECK: %z = sdiv i32 %y, 337
; CHECK: ret i32 %z
define i32 @sub1(i32 %x) {
%y = sub i32 0, %x
%z = sdiv i32 %y, 337
ret i32 %z
}
; CHECK: @sub2
; CHECK: %z = sdiv i32 %x, -337
; CHECK: ret i32 %z
define i32 @sub2(i32 %x) {
%y = sub nsw i32 0, %x
%z = sdiv i32 %y, 337
ret i32 %z
}
; CHECK: @shl_icmp
; CHECK: %B = icmp eq i64 %X, 0
; CHECK: ret i1 %B
define i1 @shl_icmp(i64 %X) nounwind {
%A = shl nuw i64 %X, 2 ; X/4
%B = icmp eq i64 %A, 0
ret i1 %B
}
; CHECK: @shl1
; CHECK: %B = shl nuw nsw i64 %A, 8
; CHECK: ret i64 %B
define i64 @shl1(i64 %X, i64* %P) nounwind {
%A = and i64 %X, 312
store i64 %A, i64* %P ; multiple uses of A.
%B = shl i64 %A, 8
ret i64 %B
}