diff options
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/lib/Transforms/Utils/SimplifyCFG.cpp | 49 | ||||
| -rw-r--r-- | llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll | 26 | ||||
| -rw-r--r-- | llvm/test/Transforms/SimplifyCFG/X86/switch_to_lookup_table.ll | 14 |
3 files changed, 7 insertions, 82 deletions
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp index daa576cfbdc..48d6a81364f 100644 --- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp @@ -3120,55 +3120,6 @@ bool SimplifyCFGOpt::SimplifyUnreachable(UnreachableInst *UI) { --i; --e; Changed = true; } - // If the default value is unreachable, figure out the most popular - // destination and make it the default. - if (SI->getDefaultDest() == BB) { - std::map<BasicBlock*, std::pair<unsigned, unsigned> > Popularity; - for (SwitchInst::CaseIt i = SI->case_begin(), e = SI->case_end(); - i != e; ++i) { - std::pair<unsigned, unsigned> &entry = - Popularity[i.getCaseSuccessor()]; - if (entry.first == 0) { - entry.first = 1; - entry.second = i.getCaseIndex(); - } else { - entry.first++; - } - } - - // Find the most popular block. - unsigned MaxPop = 0; - unsigned MaxIndex = 0; - BasicBlock *MaxBlock = nullptr; - for (std::map<BasicBlock*, std::pair<unsigned, unsigned> >::iterator - I = Popularity.begin(), E = Popularity.end(); I != E; ++I) { - if (I->second.first > MaxPop || - (I->second.first == MaxPop && MaxIndex > I->second.second)) { - MaxPop = I->second.first; - MaxIndex = I->second.second; - MaxBlock = I->first; - } - } - if (MaxBlock) { - // Make this the new default, allowing us to delete any explicit - // edges to it. - SI->setDefaultDest(MaxBlock); - Changed = true; - - // If MaxBlock has phinodes in it, remove MaxPop-1 entries from - // it. - if (isa<PHINode>(MaxBlock->begin())) - for (unsigned i = 0; i != MaxPop-1; ++i) - MaxBlock->removePredecessor(SI->getParent()); - - for (SwitchInst::CaseIt i = SI->case_begin(), e = SI->case_end(); - i != e; ++i) - if (i.getCaseSuccessor() == MaxBlock) { - SI->removeCase(i); - --i; --e; - } - } - } } else if (InvokeInst *II = dyn_cast<InvokeInst>(TI)) { if (II->getUnwindDest() == BB) { // Convert the invoke to a call instruction. This would be a good diff --git a/llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll b/llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll index 21428c62f53..22b144b5cb8 100644 --- a/llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll +++ b/llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll @@ -46,32 +46,6 @@ T: ret i32 2 } -; PR9450 -define i32 @test4(i32 %v, i32 %w) { -; CHECK: entry: -; CHECK-NEXT: switch i32 %v, label %T [ -; CHECK-NEXT: i32 3, label %V -; CHECK-NEXT: i32 2, label %U -; CHECK-NEXT: ] - -entry: - br label %SWITCH -V: - ret i32 7 -SWITCH: - switch i32 %v, label %default [ - i32 1, label %T - i32 2, label %U - i32 3, label %V - ] -default: - unreachable -U: - ret i32 %w -T: - ret i32 2 -} - ;; We can either convert the following control-flow to a select or remove the ;; unreachable control flow because of the undef store of null. Make sure we do diff --git a/llvm/test/Transforms/SimplifyCFG/X86/switch_to_lookup_table.ll b/llvm/test/Transforms/SimplifyCFG/X86/switch_to_lookup_table.ll index 95c9cc539d2..27c4839846e 100644 --- a/llvm/test/Transforms/SimplifyCFG/X86/switch_to_lookup_table.ll +++ b/llvm/test/Transforms/SimplifyCFG/X86/switch_to_lookup_table.ll @@ -21,8 +21,8 @@ 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] +; The table for @unreachable_case +; CHECK: @switch.table6 = private unnamed_addr constant [9 x i32] [i32 0, i32 0, i32 0, i32 2, i32 -1, i32 1, i32 1, i32 1, i32 1] ; A simple int-to-int selection switch. ; It is dense enough to be replaced by table lookup. @@ -752,7 +752,7 @@ return: ; CHECK: %switch.gep = getelementptr inbounds [7 x i32]* @switch.table5, i32 0, i32 %switch.tableidx } -define i32 @unreachable(i32 %x) { +define i32 @unreachable_case(i32 %x) { entry: switch i32 %x, label %sw.default [ i32 0, label %sw.bb @@ -770,15 +770,15 @@ sw.bb: br label %return sw.bb1: unreachable sw.bb2: br label %return sw.bb3: br label %return -sw.default: unreachable +sw.default: br label %return return: - %retval.0 = phi i32 [ 1, %sw.bb3 ], [ -1, %sw.bb2 ], [ 0, %sw.bb ] + %retval.0 = phi i32 [ 1, %sw.bb3 ], [ -1, %sw.bb2 ], [ 0, %sw.bb ], [ 2, %sw.default ] ret i32 %retval.0 -; CHECK-LABEL: @unreachable( +; CHECK-LABEL: @unreachable_case( ; CHECK: switch.lookup: -; CHECK: getelementptr inbounds [5 x i32]* @switch.table6, i32 0, i32 %switch.tableidx +; CHECK: getelementptr inbounds [9 x i32]* @switch.table6, i32 0, i32 %switch.tableidx } ; Don't create a table with illegal type |
