[llvm] r361581 - Revert r361460

Eli Friedman via llvm-commits llvm-commits at lists.llvm.org
Thu May 23 18:03:52 PDT 2019


Author: efriedma
Date: Thu May 23 18:03:51 2019
New Revision: 361581

URL: http://llvm.org/viewvc/llvm-project?rev=361581&view=rev
Log:
Revert r361460

It regresses https://bugs.llvm.org/show_bug.cgi?id=38309 (represented
by the testcase test/Transforms/GlobalOpt/globalsra-multigep.ll).


Removed:
    llvm/trunk/test/Transforms/GlobalOpt/globalsra-struct.ll
Modified:
    llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp
    llvm/trunk/test/Transforms/GlobalOpt/globalsra-multigep.ll

Modified: llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp?rev=361581&r1=361580&r2=361581&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp Thu May 23 18:03:51 2019
@@ -184,7 +184,7 @@ static bool IsSafeComputationToRemove(Va
 /// This GV is a pointer root.  Loop over all users of the global and clean up
 /// any that obviously don't assign the global a value that isn't dynamically
 /// allocated.
-static bool CleanupPointerRootUsers(Value *V,
+static bool CleanupPointerRootUsers(GlobalVariable *GV,
                                     const TargetLibraryInfo *TLI) {
   // A brief explanation of leak checkers.  The goal is to find bugs where
   // pointers are forgotten, causing an accumulating growth in memory
@@ -202,7 +202,7 @@ static bool CleanupPointerRootUsers(Valu
   SmallVector<std::pair<Instruction *, Instruction *>, 32> Dead;
 
   // Constants can't be pointers to dynamically allocated memory.
-  for (Value::user_iterator UI = V->user_begin(), E = V->user_end();
+  for (Value::user_iterator UI = GV->user_begin(), E = GV->user_end();
        UI != E;) {
     User *U = *UI++;
     if (StoreInst *SI = dyn_cast<StoreInst>(U)) {
@@ -232,9 +232,6 @@ static bool CleanupPointerRootUsers(Valu
           Dead.push_back(std::make_pair(I, MTI));
       }
     } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(U)) {
-      if (CE->getOpcode() == Instruction::GetElementPtr) {
-        Changed |= CleanupPointerRootUsers(CE, TLI);
-      }
       if (CE->use_empty()) {
         CE->destroyConstant();
         Changed = true;
@@ -244,7 +241,7 @@ static bool CleanupPointerRootUsers(Valu
         C->destroyConstant();
         // This could have invalidated UI, start over from scratch.
         Dead.clear();
-        CleanupPointerRootUsers(V, TLI);
+        CleanupPointerRootUsers(GV, TLI);
         return true;
       }
     }
@@ -394,22 +391,6 @@ static bool isSafeSROAGEP(User *U) {
                       [](User *UU) { return isSafeSROAElementUse(UU); });
 }
 
-/// Return true if the specified GEP is a safe user of a derived
-/// expression from a global that we want to SROA.
-static bool isSafeSubSROAGEP(User *U) {
-
-  // Check to see if this ConstantExpr GEP is SRA'able.  In particular, we
-  // don't like < 3 operand CE's, and we don't like non-constant integer
-  // indices.  This enforces that all uses are 'gep GV, 0, C, ...' for some
-  // value of C.
-  if (U->getNumOperands() < 3 || !isa<Constant>(U->getOperand(1)) ||
-      !cast<Constant>(U->getOperand(1))->isNullValue())
-    return false;
-
-  return llvm::all_of(U->users(),
-                      [](User *UU) { return isSafeSROAElementUse(UU); });
-}
-
 /// Return true if the specified instruction is a safe user of a derived
 /// expression from a global that we want to SROA.
 static bool isSafeSROAElementUse(Value *V) {
@@ -428,7 +409,7 @@ static bool isSafeSROAElementUse(Value *
     return SI->getOperand(0) != V;
 
   // Otherwise, it must be a GEP. Check it and its users are safe to SRA.
-  return isa<GetElementPtrInst>(I) && isSafeSubSROAGEP(I);
+  return isa<GetElementPtrInst>(I) && isSafeSROAGEP(I);
 }
 
 /// Look at all uses of the global and decide whether it is safe for us to

Modified: llvm/trunk/test/Transforms/GlobalOpt/globalsra-multigep.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GlobalOpt/globalsra-multigep.ll?rev=361581&r1=361580&r2=361581&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/GlobalOpt/globalsra-multigep.ll (original)
+++ llvm/trunk/test/Transforms/GlobalOpt/globalsra-multigep.ll Thu May 23 18:03:51 2019
@@ -4,20 +4,13 @@ target datalayout = "e-m:e-i64:64-f80:12
 target triple = "x86_64-unknown-linux-gnu"
 
 @g_data = internal unnamed_addr global <{ [8 x i16], [8 x i16] }> <{ [8 x i16] [i16 16, i16 16, i16 16, i16 16, i16 16, i16 16, i16 16, i16 16], [8 x i16] zeroinitializer }>, align 16
-; We normally cannot SRA here due to the second gep meaning the access to g_data may be to either element,
-; unless the value is always zero.
-; CHECK: @g_data.0 = internal unnamed_addr constant [8 x i16] [i16 16, i16 16, i16 16, i16 16, i16 16, i16 16, i16 16, i16 16], align 16
+; We cannot SRA here due to the second gep meaning the access to g_data may be to either element
+; CHECK: @g_data = internal unnamed_addr constant <{ [8 x i16], [8 x i16] }>
 
 define i16 @test(i64 %a1) {
 entry:
   %g1 = getelementptr inbounds <{ [8 x i16], [8 x i16] }>, <{ [8 x i16], [8 x i16] }>* @g_data, i64 0, i32 0
   %arrayidx.i = getelementptr inbounds [8 x i16], [8 x i16]* %g1, i64 0, i64 %a1
   %r = load i16, i16* %arrayidx.i, align 2
-
-; CHECK-NOT: getelementptr inbounds <{ [8 x i16], [8 x i16] }>, <{ [8 x i16], [8 x i16] }>* @g_data, i64 0, i32 0
-; CHECK:  %arrayidx.i = getelementptr inbounds [8 x i16], [8 x i16]* @g_data.0, i64 0, i64 %a1
-
   ret i16 %r
-
-
 }

Removed: llvm/trunk/test/Transforms/GlobalOpt/globalsra-struct.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GlobalOpt/globalsra-struct.ll?rev=361580&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/GlobalOpt/globalsra-struct.ll (original)
+++ llvm/trunk/test/Transforms/GlobalOpt/globalsra-struct.ll (removed)
@@ -1,18 +0,0 @@
-; RUN: opt < %s -globalopt -S | FileCheck %s
-
-%struct.Expr = type { [1 x i32], i32 }
-
- at e = internal global %struct.Expr zeroinitializer, align 4
-; CHECK-NOT: @e = internal global %struct.Expr zeroinitializer, align 4
-
-define dso_local i32 @foo(i32 %i) {
-entry:
-  %i.addr = alloca i32, align 4
-  store i32 %i, i32* %i.addr, align 4
-  %0 = load i32, i32* %i.addr, align 4
-  %arrayidx = getelementptr inbounds [1 x i32], [1 x i32]* getelementptr inbounds (%struct.Expr, %struct.Expr* @e, i32 0, i32 0), i32 0, i32 %0
-  store i32 57005, i32* %arrayidx, align 4
-  %1 = load i32, i32* getelementptr inbounds (%struct.Expr, %struct.Expr* @e, i32 0, i32 1), align 4
-  ret i32 %1
-; CHECK:  ret i32 0
-}




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