[llvm-commits] [llvm] r42700 - /llvm/trunk/lib/Target/X86/X86RegisterInfo.cpp

[Anton Korobeynikov]

Author: asl
Date: Sat Oct  6 11:39:43 2007
New Revision: 42700

URL: http://llvm.org/viewvc/llvm-project?rev=42700&view=rev
Log:
Oops, I really wanted to commit this part also :)

Modified:
    llvm/trunk/lib/Target/X86/X86RegisterInfo.cpp

Modified: llvm/trunk/lib/Target/X86/X86RegisterInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86RegisterInfo.cpp?rev=42700&r1=42699&r2=42700&view=diff

==============================================================================
--- llvm/trunk/lib/Target/X86/X86RegisterInfo.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86RegisterInfo.cpp Sat Oct  6 11:39:43 2007
@@ -1500,6 +1500,31 @@
   }
 }
 
+// mergeSPUpdatesUp - Merge two stack-manipulating instructions lower iterator.
+static
+void mergeSPUpdatesDown(MachineBasicBlock &MBB,MachineBasicBlock::iterator &MBBI,
+                        unsigned StackPtr, uint64_t *NumBytes = NULL) {
+  if (MBBI != MBB.end()) {
+    MachineBasicBlock::iterator NI = next(MBBI);
+    unsigned Opc = NI->getOpcode();
+    if ((Opc == X86::ADD64ri32 || Opc == X86::ADD64ri8 ||
+         Opc == X86::ADD32ri || Opc == X86::ADD32ri8) &&
+        NI->getOperand(0).getReg() == StackPtr) {
+      if (NumBytes)
+        *NumBytes -= NI->getOperand(2).getImm();
+      MBB.erase(NI);
+      MBBI = NI;
+    } else if ((Opc == X86::SUB64ri32 || Opc == X86::SUB64ri8 ||
+                Opc == X86::SUB32ri || Opc == X86::SUB32ri8) &&
+               NI->getOperand(0).getReg() == StackPtr) {
+      if (NumBytes)
+        *NumBytes += NI->getOperand(2).getImm();
+      MBB.erase(NI);
+      MBBI = NI;
+    }
+  }
+}
+
 void X86RegisterInfo::emitPrologue(MachineFunction &MF) const {
   MachineBasicBlock &MBB = MF.front();   // Prolog goes in entry BB
   MachineFrameInfo *MFI = MF.getFrameInfo();
@@ -1585,9 +1610,9 @@
         MBB.insert(MBBI, MI);
       }
     } else {
-      // If there is an ADD32ri or SUB32ri of ESP immediately before this
+      // If there is an ADD32ri or SUB32ri of ESP immediately after this
       // instruction, merge the two instructions.
-      mergeSPUpdatesUp(MBB, MBBI, StackPtr, &NumBytes);
+      mergeSPUpdatesDown(MBB, MBBI, StackPtr, &NumBytes);
       
       if (NumBytes)
         emitSPUpdate(MBB, MBBI, StackPtr, -(int64_t)NumBytes, Is64Bit, TII);