Replace the use of isPredicable() with isPredicated() in

MachineBasicBlock::canFallThrough().  We're interested in the state of the
instruction (i.e., is this a barrier or not?), not if the instruction is
predicable or not.
rdar://10501092

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149070 91177308-0d34-0410-b5e6-96231b3b80d8

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.

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}