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
This commit is contained in:
Chad Rosier 2012-01-26 18:24:25 +00:00
parent 1a96c91431
commit 0162ff421d
2 changed files with 46 additions and 3 deletions

View File

@ -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.

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@ -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}