diff options
| -rw-r--r-- | lib/CodeGen/MachineBasicBlock.cpp | 5 | ||||
| -rw-r--r-- | test/CodeGen/ARM/tail-dup.ll | 44 |
2 files changed, 46 insertions, 3 deletions
diff --git a/lib/CodeGen/MachineBasicBlock.cpp b/lib/CodeGen/MachineBasicBlock.cpp index b4a2ca1894..0205c0af05 100644 --- a/lib/CodeGen/MachineBasicBlock.cpp +++ b/lib/CodeGen/MachineBasicBlock.cpp @@ -535,13 +535,12 @@ bool MachineBasicBlock::canFallThrough() { if (TII->AnalyzeBranch(*this, TBB, FBB, Cond)) { // If we couldn't analyze the branch, examine the last instruction. // If the block doesn't end in a known control barrier, assume fallthrough - // is possible. The isPredicable check is needed because this code can be + // is possible. The isPredicated check is needed because this code can be // called during IfConversion, where an instruction which is normally a // Barrier is predicated and thus no longer an actual control barrier. This // is over-conservative though, because if an instruction isn't actually // predicated we could still treat it like a barrier. - return empty() || !back().isBarrier() || - back().isPredicable(); + return empty() || !back().isBarrier() || TII->isPredicated(&back()); } // If there is no branch, control always falls through. diff --git a/test/CodeGen/ARM/tail-dup.ll b/test/CodeGen/ARM/tail-dup.ll new file mode 100644 index 0000000000..e015bf098f --- /dev/null +++ b/test/CodeGen/ARM/tail-dup.ll @@ -0,0 +1,44 @@ +; RUN: llc < %s -mtriple=thumb-apple-darwin -relocation-model=dynamic-no-pic -mcpu=cortex-a8 -asm-verbose=false | FileCheck %s + +; We should be able to tail-duplicate the basic block containing the indirectbr +; into all of its predecessors. +; CHECK: fn: +; CHECK: mov pc +; CHECK: mov pc +; CHECK: mov pc + +@fn.codetable = internal unnamed_addr constant [3 x i8*] [i8* blockaddress(@fn, %RETURN), i8* blockaddress(@fn, %INCREMENT), i8* blockaddress(@fn, %DECREMENT)], align 4 + +define i32 @fn(i32* nocapture %opcodes) nounwind readonly ssp { +entry: + %0 = load i32* %opcodes, align 4, !tbaa !0 + %arrayidx = getelementptr inbounds [3 x i8*]* @fn.codetable, i32 0, i32 %0 + br label %indirectgoto + +INCREMENT: ; preds = %indirectgoto + %inc = add nsw i32 %result.0, 1 + %1 = load i32* %opcodes.addr.0, align 4, !tbaa !0 + %arrayidx2 = getelementptr inbounds [3 x i8*]* @fn.codetable, i32 0, i32 %1 + br label %indirectgoto + +DECREMENT: ; preds = %indirectgoto + %dec = add nsw i32 %result.0, -1 + %2 = load i32* %opcodes.addr.0, align 4, !tbaa !0 + %arrayidx4 = getelementptr inbounds [3 x i8*]* @fn.codetable, i32 0, i32 %2 + br label %indirectgoto + +indirectgoto: ; preds = %DECREMENT, %INCREMENT, %entry + %result.0 = phi i32 [ 0, %entry ], [ %dec, %DECREMENT ], [ %inc, %INCREMENT ] + %opcodes.pn = phi i32* [ %opcodes, %entry ], [ %opcodes.addr.0, %DECREMENT ], [ %opcodes.addr.0, %INCREMENT ] + %indirect.goto.dest.in = phi i8** [ %arrayidx, %entry ], [ %arrayidx4, %DECREMENT ], [ %arrayidx2, %INCREMENT ] + %opcodes.addr.0 = getelementptr inbounds i32* %opcodes.pn, i32 1 + %indirect.goto.dest = load i8** %indirect.goto.dest.in, align 4 + indirectbr i8* %indirect.goto.dest, [label %RETURN, label %INCREMENT, label %DECREMENT] + +RETURN: ; preds = %indirectgoto + ret i32 %result.0 +} + +!0 = metadata !{metadata !"int", metadata !1} +!1 = metadata !{metadata !"omnipotent char", metadata !2} +!2 = metadata !{metadata !"Simple C/C++ TBAA", null} |