diff options
| -rw-r--r-- | lib/Transforms/Utils/SimplifyCFG.cpp | 2 | ||||
| -rw-r--r-- | test/Transforms/SimplifyCFG/switch_to_lookup_table.ll | 32 |
2 files changed, 32 insertions, 2 deletions
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp index a477aa58cf..96e3fdca1b 100644 --- a/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/lib/Transforms/Utils/SimplifyCFG.cpp @@ -3545,8 +3545,6 @@ static bool SwitchToLookupTable(SwitchInst *SI, if (TTI && !TTI->getScalarTargetTransformInfo()->shouldBuildLookupTables()) return false; - // FIXME: Handle unreachable cases. - // FIXME: If the switch is too sparse for a lookup table, perhaps we could // split off a dense part and build a lookup table for that. diff --git a/test/Transforms/SimplifyCFG/switch_to_lookup_table.ll b/test/Transforms/SimplifyCFG/switch_to_lookup_table.ll index 39469cd9cf..d358350554 100644 --- a/test/Transforms/SimplifyCFG/switch_to_lookup_table.ll +++ b/test/Transforms/SimplifyCFG/switch_to_lookup_table.ll @@ -21,6 +21,9 @@ target triple = "x86_64-unknown-linux-gnu" ; The table for @cprop ; CHECK: @switch.table5 = private unnamed_addr constant [7 x i32] [i32 5, i32 42, i32 126, i32 -452, i32 128, i32 6, i32 7] +; The table for @unreachable +; CHECK: @switch.table6 = private unnamed_addr constant [5 x i32] [i32 0, i32 0, i32 0, i32 1, i32 -1] + ; A simple int-to-int selection switch. ; It is dense enough to be replaced by table lookup. ; The result is directly by a ret from an otherwise empty bb, @@ -745,3 +748,32 @@ return: ; CHECK: switch.lookup: ; CHECK: %switch.gep = getelementptr inbounds [7 x i32]* @switch.table5, i32 0, i32 %switch.tableidx } + +define i32 @unreachable(i32 %x) { +entry: + switch i32 %x, label %sw.default [ + i32 0, label %sw.bb + i32 1, label %sw.bb + i32 2, label %sw.bb + i32 3, label %sw.bb1 + i32 4, label %sw.bb2 + i32 5, label %sw.bb3 + i32 6, label %sw.bb3 + i32 7, label %sw.bb3 + i32 8, label %sw.bb3 + ] + +sw.bb: br label %return +sw.bb1: unreachable +sw.bb2: br label %return +sw.bb3: br label %return +sw.default: unreachable + +return: + %retval.0 = phi i32 [ 1, %sw.bb3 ], [ -1, %sw.bb2 ], [ 1, %sw.bb1 ], [ 0, %sw.bb ] + ret i32 %retval.0 + +; CHECK: @unreachable +; CHECK: switch.lookup: +; CHECK: getelementptr inbounds [5 x i32]* @switch.table6, i32 0, i32 %switch.tableidx +} |