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llvm-mirror/test/Transforms/InstCombine/2006-04-28-ShiftShiftLongLong.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

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LLVM

; RUN: opt < %s -instcombine -S | FileCheck %s
; This cannot be turned into a sign extending cast!
define i64 @test(i64 %X) {
%Y = shl i64 %X, 16 ; <i64> [#uses=1]
; CHECK: %Y = shl i64 %X, 16
%Z = ashr i64 %Y, 16 ; <i64> [#uses=1]
; CHECK: %Z = ashr exact i64 %Y, 16
ret i64 %Z
; CHECK: ret i64 %Z
}