Perform an intelligent splice of the predecessor with the single successor.

If the predecessor's being spliced into a landing pad, then we need the PHIs to
come first and the rest of the predecessor's code to come *after* the landing
pad instruction.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193035 91177308-0d34-0410-b5e6-96231b3b80d8
Remove unused variable.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193038 91177308-0d34-0410-b5e6-96231b3b80d8
Emit DWARF line entries for all data in the instruction stream.

r182712 attempted to do this, but it failed to handle data emitted via
EmitBytes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193041 91177308-0d34-0410-b5e6-96231b3b80d8
Emit prefix data after debug and EH directives.

This ensures that the prefix data is treated as part of the function for
the purpose of debug info.  This provides a better debugging experience,
among other things by allowing a debug info client to correctly look up
a function in debug info given a function pointer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193042 91177308-0d34-0410-b5e6-96231b3b80d8
Typo.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193043 91177308-0d34-0410-b5e6-96231b3b80d8
Teach simplify-cfg how to correctly create covered lookup tables for switches on iN with N >= 3.

One optimization simplify-cfg performs is the converting of switches to
lookup tables if the switch has > 4 cases. This is done by:

1. Finding the max/min case value and calculating the switch case range.
2. Create a lookup table basic block.
3. Perform a check in the switch's BB to see if the input value is in
the switch's case range. If the input value satisfies said predicate
branch to the lookup table BB, otherwise branch to the switch's default
destination BB using the default value as the result.

The conditional check consists of subtracting the min case value of the
table from any input iN value and then ensuring that said value is
unsigned less than the size of the lookup table represented as an iN
value.

If the lookup table is a covered lookup table, the size of the table will be N
which is 0 as an iN value. Thus the comparison will be an `icmp ult` of an iN
value against 0 which is always false yielding the incorrect result.

This patch fixes this problem by recognizing if we have a covered lookup table
and if we do, unconditionally jumps to the lookup table BB since the covering
property of the lookup table implies no input values could not be handled by
said BB.

rdar://15268442

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193045 91177308-0d34-0410-b5e6-96231b3b80d8