PPC: Prep for if conversion of bctr[l]
This adds in-principle support for if-converting the bctr[l] instructions.
These instructions are used for indirect branching. It seems, however, that the
current if converter will never actually predicate these. To do so, it would
need the ability to hoist a few setup insts. out of the conditionally-executed
block. For example, code like this:
void foo(int a, int (*bar)()) { if (a != 0) bar(); }
becomes:
...
beq 0, .LBB0_2
std 2, 40(1)
mr 12, 4
ld 3, 0(4)
ld 11, 16(4)
ld 2, 8(4)
mtctr 3
bctrl
ld 2, 40(1)
.LBB0_2:
...
and it would be safe to do all of this unconditionally with a predicated
beqctrl instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179156 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCInstrInfo.td b/lib/Target/PowerPC/PPCInstrInfo.td
index 11969fe..6c12f68 100644
--- a/lib/Target/PowerPC/PPCInstrInfo.td
+++ b/lib/Target/PowerPC/PPCInstrInfo.td
@@ -493,8 +493,12 @@
let isReturn = 1, Uses = [LR, RM] in
def BLR : XLForm_2_ext<19, 16, 20, 0, 0, (outs), (ins), "blr", BrB,
[(retflag)]>;
- let isBranch = 1, isIndirectBranch = 1, Uses = [CTR] in
+ let isBranch = 1, isIndirectBranch = 1, Uses = [CTR] in {
def BCTR : XLForm_2_ext<19, 528, 20, 0, 0, (outs), (ins), "bctr", BrB, []>;
+
+ def BCCTR : XLForm_2_br<19, 528, 0, (outs), (ins pred:$cond),
+ "b${cond:cc}ctr ${cond:reg}", BrB, []>;
+ }
}
let Defs = [LR] in
@@ -555,6 +559,8 @@
def BCTRL : XLForm_2_ext<19, 528, 20, 0, 1, (outs), (ins),
"bctrl", BrB, [(PPCbctrl)]>,
Requires<[In32BitMode]>;
+ def BCCTRL : XLForm_2_br<19, 528, 1, (outs), (ins pred:$cond),
+ "b${cond:cc}ctrl ${cond:reg}", BrB, []>;
}
}