Fix a bug in outputting branches to constant PCs. Since the PC is supplied as

a full 64-bit address, it must be adjusted to fit in the branch instruction's
immediate field. (This is only used in the reoptimizer, for now.)

llvm-svn: 13608

1 files changed, 3 insertions, 2 deletions

diff --git a/llvm/lib/Target/SparcV9/SparcV9CodeEmitter.cpp b/llvm/lib/Target/SparcV9/SparcV9CodeEmitter.cpp
index 6606d8d6460..4fc221325a8 100644
--- a/llvm/lib/Target/SparcV9/SparcV9CodeEmitter.cpp
+++ b/llvm/lib/Target/SparcV9/SparcV9CodeEmitter.cpp
@@ -597,8 +597,9 @@ int64_t SparcV9CodeEmitter::getMachineOpValue(MachineInstr &MI,
       unsigned* CurrPC = (unsigned*)(intptr_t)MCE.getCurrentPCValue();
       BBRefs.push_back(std::make_pair(BB, std::make_pair(CurrPC, &MI)));
     } else if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
-      // Make constant PC-relative by subtracting the PC from it.
-      rv = CI->getRawValue() - MCE.getCurrentPCValue();
+      // The real target of the branch is CI = PC + (rv * 4)
+      // So undo that: give the instruction (CI - PC) / 4
+      rv = (CI->getRawValue() - MCE.getCurrentPCValue()) / 4;
     } else if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
       // same as MO.isGlobalAddress()
       DEBUG(std::cerr << "GlobalValue: ");