Fix a FIXME: Select instructions on longs were miscompiled.
While we're at it, improve codegen of select instructions. For this
testcase:
int %test(bool %C, int %A, int %B) {
%D = select bool %C, int %A, int %B
ret int %D
}
We used to generate this code:
_test:
cmpwi cr0, r3, 0
bne .LBB_test_2 ;
.LBB_test_1: ;
b .LBB_test_3 ;
.LBB_test_2: ;
or r5, r4, r4
.LBB_test_3: ;
or r3, r5, r5
blr
Now we emit:
_test:
cmpwi cr0, r3, 0
bne .LBB_test_2 ;
.LBB_test_1: ;
or r4, r5, r5
.LBB_test_2: ;
or r3, r4, r4
blr
-Chris
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19214 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPC32ISelSimple.cpp b/lib/Target/PowerPC/PPC32ISelSimple.cpp
index bd6c7e4..a56416d 100644
--- a/lib/Target/PowerPC/PPC32ISelSimple.cpp
+++ b/lib/Target/PowerPC/PPC32ISelSimple.cpp
@@ -1429,34 +1429,25 @@
// thisMBB:
// ...
+ // TrueVal = ...
// cmpTY cr0, r1, r2
// bCC copy1MBB
// fallthrough --> copy0MBB
MachineBasicBlock *copy0MBB = new MachineBasicBlock(LLVM_BB);
- MachineBasicBlock *copy1MBB = new MachineBasicBlock(LLVM_BB);
MachineBasicBlock *sinkMBB = new MachineBasicBlock(LLVM_BB);
- BuildMI(BB, Opcode, 2).addReg(PPC::CR0).addMBB(copy1MBB);
+ unsigned TrueValue = getReg(TrueVal, BB, BB->begin());
+ BuildMI(BB, Opcode, 2).addReg(PPC::CR0).addMBB(sinkMBB);
F->getBasicBlockList().insert(It, copy0MBB);
- F->getBasicBlockList().insert(It, copy1MBB);
F->getBasicBlockList().insert(It, sinkMBB);
// Update machine-CFG edges
BB->addSuccessor(copy0MBB);
- BB->addSuccessor(copy1MBB);
+ BB->addSuccessor(sinkMBB);
// copy0MBB:
// %FalseValue = ...
- // b sinkMBB
+ // # fallthrough to sinkMBB
BB = copy0MBB;
unsigned FalseValue = getReg(FalseVal, BB, BB->begin());
- BuildMI(BB, PPC::B, 1).addMBB(sinkMBB);
- // Update machine-CFG edges
- BB->addSuccessor(sinkMBB);
-
- // copy1MBB:
- // %TrueValue = ...
- // fallthrough
- BB = copy1MBB;
- unsigned TrueValue = getReg(TrueVal, BB, BB->begin());
// Update machine-CFG edges
BB->addSuccessor(sinkMBB);
@@ -1465,13 +1456,12 @@
// ...
BB = sinkMBB;
BuildMI(BB, PPC::PHI, 4, DestReg).addReg(FalseValue)
- .addMBB(copy0MBB).addReg(TrueValue).addMBB(copy1MBB);
+ .addMBB(copy0MBB).addReg(TrueValue).addMBB(thisMBB);
- // For a register pair representing a long value, define the second reg
- // FIXME: Can this really be correct for selecting longs?
+ // For a register pair representing a long value, define the top part.
if (getClassB(TrueVal->getType()) == cLong)
- BuildMI(BB, PPC::LI, 1, DestReg+1).addImm(0);
- return;
+ BuildMI(BB, PPC::PHI, 4, DestReg+1).addReg(FalseValue+1)
+ .addMBB(copy0MBB).addReg(TrueValue+1).addMBB(thisMBB);
}