llvm/test/Transforms/InstCombine/pr8547.ll
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

26 lines
903 B
LLVM

; RUN: opt < %s -instcombine -S | FileCheck %s
; Converting the 2 shifts to SHL 6 without the AND is wrong. PR 8547.
@g_2 = global i32 0, align 4
@.str = constant [10 x i8] c"g_2 = %d\0A\00"
declare i32 @printf(i8*, ...)
define i32 @main() nounwind {
codeRepl:
br label %for.cond
for.cond: ; preds = %for.cond, %codeRepl
%storemerge = phi i32 [ 0, %codeRepl ], [ 5, %for.cond ]
store i32 %storemerge, i32* @g_2, align 4
%shl = shl i32 %storemerge, 30
%conv2 = lshr i32 %shl, 24
; CHECK: %0 = shl nuw nsw i32 %storemerge, 6
; CHECK: %conv2 = and i32 %0, 64
%tobool = icmp eq i32 %conv2, 0
br i1 %tobool, label %for.cond, label %codeRepl2
codeRepl2: ; preds = %for.cond
%call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([10 x i8]* @.str, i64 0, i64 0), i32 %conv2) nounwind
ret i32 0
}