[llvm-commits] [llvm] r144787 - /llvm/trunk/lib/CodeGen/SjLjEHPrepare.cpp

[Bob Wilson]

Author: bwilson
Date: Wed Nov 16 01:57:21 2011
New Revision: 144787

URL: http://llvm.org/viewvc/llvm-project?rev=144787&view=rev
Log:
Record landing pads with a SmallSetVector to avoid multiple entries.

There may be many invokes that share one landing pad, and the previous code
would record the landing pad once for each invoke.  Besides the wasted
effort, a pair of volatile loads gets inserted every time the landing pad is
processed.  The rest of the code can get optimized away when a landing pad
is processed repeatedly, but the volatile loads remain, resulting in code like:

LBB35_18:
Ltmp483:
        ldr     r2, [r7, #-72]
        ldr     r2, [r7, #-68]
        ldr     r2, [r7, #-72]
        ldr     r2, [r7, #-68]
        ldr     r2, [r7, #-72]
        ldr     r2, [r7, #-68]
        ldr     r2, [r7, #-72]
        ldr     r2, [r7, #-68]
        ldr     r2, [r7, #-72]
        ldr     r2, [r7, #-68]
        ldr     r2, [r7, #-72]
        ldr     r2, [r7, #-68]
        ldr     r2, [r7, #-72]
        ldr     r2, [r7, #-68]
        ldr     r2, [r7, #-72]
        ldr     r2, [r7, #-68]
        ldr     r4, [r7, #-72]
        ldr     r2, [r7, #-68]

Modified:
    llvm/trunk/lib/CodeGen/SjLjEHPrepare.cpp

Modified: llvm/trunk/lib/CodeGen/SjLjEHPrepare.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SjLjEHPrepare.cpp?rev=144787&r1=144786&r2=144787&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SjLjEHPrepare.cpp (original)
+++ llvm/trunk/lib/CodeGen/SjLjEHPrepare.cpp Wed Nov 16 01:57:21 2011
@@ -30,6 +30,7 @@
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/IRBuilder.h"
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
@@ -364,13 +365,13 @@
 bool SjLjEHPass::setupEntryBlockAndCallSites(Function &F) {
   SmallVector<ReturnInst*,     16> Returns;
   SmallVector<InvokeInst*,     16> Invokes;
-  SmallVector<LandingPadInst*, 16> LPads;
+  SmallSetVector<LandingPadInst*, 16> LPads;
 
   // Look through the terminators of the basic blocks to find invokes.
   for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
     if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator())) {
       Invokes.push_back(II);
-      LPads.push_back(II->getUnwindDest()->getLandingPadInst());
+      LPads.insert(II->getUnwindDest()->getLandingPadInst());
     } else if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) {
       Returns.push_back(RI);
     }
@@ -382,7 +383,8 @@
   lowerIncomingArguments(F);
   lowerAcrossUnwindEdges(F, Invokes);
 
-  Value *FuncCtx = setupFunctionContext(F, LPads);
+  Value *FuncCtx =
+    setupFunctionContext(F, makeArrayRef(LPads.begin(), LPads.end()));
   BasicBlock *EntryBB = F.begin();
   Type *Int32Ty = Type::getInt32Ty(F.getContext());