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.)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13608 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/SparcV9/SparcV9CodeEmitter.cpp b/lib/Target/SparcV9/SparcV9CodeEmitter.cpp
index 6606d8d6460070043ea6e77fc10df696e06d6b37..4fc221325a87a7467b40227d3591fd19bc3162fa 100644 (file)
--- a/lib/Target/SparcV9/SparcV9CodeEmitter.cpp
+++ b/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: ");