Created
March 3, 2013 00:14
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| ; ModuleID = 'llvm-re' | |
| @transitiontable = internal constant [3 x [2 x i32]] [[2 x i32] [i32 1, i32 -1], [2 x i32] [i32 -1, i32 2], [2 x i32] [i32 3, i32 -1]] | |
| define i32 @match(i8*) { | |
| entry: | |
| %Index = alloca i32 | |
| store i32 0, i32* %Index | |
| %IsMatch = alloca i32 | |
| store i32 0, i32* %IsMatch | |
| %CurState = alloca i32 | |
| store i32 0, i32* %CurState | |
| br label %loop.start | |
| fail: ; preds = %loop.start | |
| ret i32 0 | |
| success: ; preds = %loop.end | |
| ret i32 1 | |
| loop.start: ; preds = %loop.end, %entry | |
| %1 = load i32* %Index | |
| %CurChar = getelementptr i8* %0, i32 %1 | |
| %2 = load i8* %CurChar | |
| %3 = call i32 @getcharindex(i8 %2) | |
| %4 = load i32* %CurState | |
| %5 = getelementptr [3 x [2 x i32]]* @transitiontable, i32 0, i32 %4, i32 %3 | |
| %6 = load i32* %5 | |
| %7 = icmp eq i32 %6, -1 | |
| br i1 %7, label %fail, label %loop.end | |
| loop.end: ; preds = %loop.start | |
| store i32 %6, i32* %CurState | |
| %8 = load i32* %Index | |
| %9 = add i32 %8, 1 | |
| store i32 %9, i32* %Index | |
| %10 = icmp eq i32 %6, 3 | |
| br i1 %10, label %success, label %loop.start | |
| } | |
| define internal i32 @getcharindex(i8) { | |
| entry: | |
| switch i8 %0, label %default [ | |
| i8 97, label %1 | |
| i8 98, label %2 | |
| ] | |
| default: ; preds = %entry | |
| ret i32 -1 | |
| ; <label>:1 ; preds = %entry | |
| ret i32 0 | |
| ; <label>:2 ; preds = %entry | |
| ret i32 1 | |
| } | |
| optimised: | |
| @transitiontable = internal unnamed_addr constant [3 x [2 x i32]] [[2 x i32] [i32 1, i32 -1], [2 x i32] [i32 -1, i32 2], [2 x i32] [i32 3, i32 -1]] | |
| define i32 @match(i8* nocapture) #0 { | |
| entry: | |
| br label %loop.start | |
| fail: ; preds = %loop.end, %getcharindex.exit | |
| %merge = phi i32 [ 0, %getcharindex.exit ], [ 1, %loop.end ] | |
| ret i32 %merge | |
| loop.start: ; preds = %loop.end, %entry | |
| %1 = phi i32 [ %7, %loop.end ], [ 0, %entry ] | |
| %2 = phi i32 [ %9, %loop.end ], [ 0, %entry ] | |
| %CurChar = getelementptr i8* %0, i32 %2 | |
| %3 = load i8* %CurChar | |
| switch i8 %3, label %getcharindex.exit [ | |
| i8 97, label %4 | |
| i8 98, label %5 | |
| ] | |
| ; <label>:4 ; preds = %loop.start | |
| br label %getcharindex.exit | |
| ; <label>:5 ; preds = %loop.start | |
| br label %getcharindex.exit | |
| getcharindex.exit: ; preds = %loop.start, %4, %5 | |
| %merge.i = phi i32 [ -1, %loop.start ], [ 0, %4 ], [ 1, %5 ] | |
| %6 = getelementptr [3 x [2 x i32]]* @transitiontable, i32 0, i32 %1, i32 %merge.i | |
| %7 = load i32* %6 | |
| %8 = icmp eq i32 %7, -1 | |
| br i1 %8, label %fail, label %loop.end | |
| loop.end: ; preds = %getcharindex.exit | |
| %9 = add i32 %2, 1 | |
| %10 = icmp eq i32 %7, 3 | |
| br i1 %10, label %fail, label %loop.start | |
| } | |
| attributes #0 = { nounwind readonly } |
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