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Diffstat (limited to 'lib/Target/README.txt')
| -rw-r--r-- | lib/Target/README.txt | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/lib/Target/README.txt b/lib/Target/README.txt index 4d7ee08de1de..4faf8bcfd419 100644 --- a/lib/Target/README.txt +++ b/lib/Target/README.txt @@ -1919,5 +1919,21 @@ something like the following, which eliminates a branch: ret .LBB0_2: jmp foo # TAILCALL +//===---------------------------------------------------------------------===// +Given a branch where the two target blocks are identical ("ret i32 %b" in +both), simplifycfg will simplify them away. But not so for a switch statement: + +define i32 @f(i32 %a, i32 %b) nounwind readnone { +entry: + switch i32 %a, label %bb3 [ + i32 4, label %bb + i32 6, label %bb + ] +bb: ; preds = %entry, %entry + ret i32 %b + +bb3: ; preds = %entry + ret i32 %b +} //===---------------------------------------------------------------------===// |