diff options
| -rw-r--r-- | lib/CodeGen/BranchFolding.cpp | 15 | ||||
| -rw-r--r-- | test/CodeGen/X86/2009-05-11-tailmerge-crash.ll | 23 |
2 files changed, 38 insertions, 0 deletions
diff --git a/lib/CodeGen/BranchFolding.cpp b/lib/CodeGen/BranchFolding.cpp index 583009c..2635303 100644 --- a/lib/CodeGen/BranchFolding.cpp +++ b/lib/CodeGen/BranchFolding.cpp @@ -1092,6 +1092,21 @@ void BranchFolder::OptimizeBlock(MachineBasicBlock *MBB) { } else { DidChange = true; PMBB->ReplaceUsesOfBlockWith(MBB, CurTBB); + // If this change resulted in PMBB ending in a conditional + // branch where both conditions go to the same destination, + // change this to an unconditional branch (and fix the CFG). + MachineBasicBlock *NewCurTBB = 0, *NewCurFBB = 0; + SmallVector<MachineOperand, 4> NewCurCond; + bool NewCurUnAnalyzable = TII->AnalyzeBranch(*PMBB, NewCurTBB, + NewCurFBB, NewCurCond, true); + if (!NewCurUnAnalyzable && NewCurTBB && NewCurTBB == NewCurFBB) { + TII->RemoveBranch(*PMBB); + NewCurCond.clear(); + TII->InsertBranch(*PMBB, NewCurTBB, 0, NewCurCond); + MadeChange = true; + ++NumBranchOpts; + PMBB->CorrectExtraCFGEdges(NewCurTBB, NewCurFBB, false); + } } } diff --git a/test/CodeGen/X86/2009-05-11-tailmerge-crash.ll b/test/CodeGen/X86/2009-05-11-tailmerge-crash.ll new file mode 100644 index 0000000..8178725 --- /dev/null +++ b/test/CodeGen/X86/2009-05-11-tailmerge-crash.ll @@ -0,0 +1,23 @@ +; RUN: llvm-as < %s | llc -march=x86 +; PR4188 +; ModuleID = '<stdin>' +target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128" +target triple = "i386-apple-darwin9.6" +@g_9 = external global i32 ; <i32*> [#uses=1] + +define i32 @int86(i32 %p_87) nounwind { +entry: + %0 = trunc i32 %p_87 to i8 ; <i8> [#uses=1] + %1 = icmp ne i8 %0, 0 ; <i1> [#uses=1] + br label %bb + +bb: ; preds = %bb.i, %bb, %entry + %2 = volatile load i32* @g_9, align 4 ; <i32> [#uses=2] + %3 = icmp sgt i32 %2, 1 ; <i1> [#uses=1] + %4 = and i1 %3, %1 ; <i1> [#uses=1] + br i1 %4, label %bb.i, label %bb + +bb.i: ; preds = %bb + %5 = icmp sgt i32 0, %2 ; <i1> [#uses=0] + br label %bb +} |