Use conservative size estimate for tBR_JTr.
This pseudo-instruction contains a .align directive in its expansion, so
the total size may vary by 2 bytes.
It is too difficult to accurately keep track of this alignment
directive, just use the worst-case size instead.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145971 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMConstantIslandPass.cpp b/lib/Target/ARM/ARMConstantIslandPass.cpp
index c8b2fc1..6d39a66 100644
--- a/lib/Target/ARM/ARMConstantIslandPass.cpp
+++ b/lib/Target/ARM/ARMConstantIslandPass.cpp
@@ -525,13 +525,8 @@
// A Thumb1 table jump may involve padding; for the offsets to
// be right, functions containing these must be 4-byte aligned.
// tBR_JTr expands to a mov pc followed by .align 2 and then the jump
- // table entries. So this code checks whether offset of tBR_JTr + 2
- // is aligned. That is held in Offset+MBBSize, which already has
- // 2 added in for the size of the mov pc instruction.
+ // table entries. GetInstSizeInBytes returns the worst case size.
MF.EnsureAlignment(2U);
- if ((Offset+MBBSize)%4 != 0 || HasInlineAsm)
- // FIXME: Add a pseudo ALIGN instruction instead.
- MBBSize += 2; // padding
continue; // Does not get an entry in ImmBranches
case ARM::t2BR_JT:
T2JumpTables.push_back(I);
@@ -809,23 +804,6 @@
// Set the size of NewBB in BBSizes. It does not include any padding now.
BBSizes[NewBBI] = NewBBSize;
- MachineInstr* ThumbJTMI = prior(NewBB->end());
- if (ThumbJTMI->getOpcode() == ARM::tBR_JTr) {
- // We've added another 2-byte instruction before this tablejump, which
- // means we will always need padding if we didn't before, and vice versa.
-
- // The original offset of the jump instruction was:
- unsigned OrigOffset = BBOffsets[OrigBBI] + BBSizes[OrigBBI] - delta;
- if (OrigOffset%4 == 0) {
- // We had padding before and now we don't. No net change in code size.
- delta = 0;
- } else {
- // We didn't have padding before and now we do.
- BBSizes[NewBBI] += 2;
- delta = 4;
- }
- }
-
// All BBOffsets following these blocks must be modified.
if (delta)
AdjustBBOffsetsAfter(NewBB, delta);