llvm-6502/test/CodeGen/X86/2009-07-20-DAGCombineBug.ll
Evan Cheng d101a72d79 Fix a dagga combiner bug: avoid creating illegal constant.
Is this really a winning transformation?
fold (shl (srl x, c1), c2) -> (shl (and x, (shl -1, c1)), (sub c2, c1)) or                                                                              
                              (srl (and x, (shl -1, c1)), (sub c1, c2))


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@76535 91177308-0d34-0410-b5e6-96231b3b80d8
2009-07-21 05:40:15 +00:00

30 lines
827 B
LLVM

; RUN: llvm-as < %s | llc -march=x86
@bsBuff = internal global i32 0 ; <i32*> [#uses=1]
@llvm.used = appending global [1 x i8*] [i8* bitcast (i32 ()* @bsGetUInt32 to i8*)], section "llvm.metadata" ; <[1 x i8*]*> [#uses=0]
define fastcc i32 @bsGetUInt32() nounwind ssp {
entry:
%bsBuff.promoted44 = load i32* @bsBuff ; <i32> [#uses=1]
%0 = add i32 0, -8 ; <i32> [#uses=1]
%1 = lshr i32 %bsBuff.promoted44, %0 ; <i32> [#uses=1]
%2 = shl i32 %1, 8 ; <i32> [#uses=1]
br label %bb3.i17
bb3.i9: ; preds = %bb3.i17
br i1 false, label %bb2.i16, label %bb1.i15
bb1.i15: ; preds = %bb3.i9
unreachable
bb2.i16: ; preds = %bb3.i9
br label %bb3.i17
bb3.i17: ; preds = %bb2.i16, %entry
br i1 false, label %bb3.i9, label %bsR.exit18
bsR.exit18: ; preds = %bb3.i17
%3 = or i32 0, %2 ; <i32> [#uses=0]
ret i32 0
}