the processor keeps a return addresses stack (RAS) which stores the address
and the instruction execution state of the instruction after a function-call
type branch instruction.
Calling a "noreturn" function with normal call instructions (e.g. bl) can
corrupt RAS and causes 100% return misprediction so LLVM should use a
unconditional branch instead. i.e.
mov lr, pc
b _foo
The "mov lr, pc" is issued in order to get proper backtrace.
rdar://8979299
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151623 91177308-0d34-0410-b5e6-96231b3b80d8
with a vector condition); such selects become VSELECT codegen nodes.
This patch also removes VSETCC codegen nodes, unifying them with SETCC
nodes (codegen was actually often using SETCC for vector SETCC already).
This ensures that various DAG combiner optimizations kick in for vector
comparisons. Passes dragonegg bootstrap with no testsuite regressions
(nightly testsuite as well as "make check-all"). Patch mostly by
Nadav Rotem.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139159 91177308-0d34-0410-b5e6-96231b3b80d8
- expansion of SELECT_CC into SETCC
- force SETCC result type to i1
- custom selection for handling i1 using SETCC
Patch by Dan Bailey
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130358 91177308-0d34-0410-b5e6-96231b3b80d8
- Emit mad instead of mad.rn for shader model 1.0
- Emit explicit mov.u32 instructions for reading global variables
- (most PTX instructions cannot take global variable immediates)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127895 91177308-0d34-0410-b5e6-96231b3b80d8
