diff options
| -rw-r--r-- | llvm/lib/Transforms/IPO/GlobalOpt.cpp | 27 | ||||
| -rw-r--r-- | llvm/test/Transforms/GlobalOpt/globalsra-multigep.ll | 11 | ||||
| -rw-r--r-- | llvm/test/Transforms/GlobalOpt/globalsra-struct.ll | 18 |
3 files changed, 50 insertions, 6 deletions
diff --git a/llvm/lib/Transforms/IPO/GlobalOpt.cpp b/llvm/lib/Transforms/IPO/GlobalOpt.cpp index c4fb3ce77f6..c4f268a6511 100644 --- a/llvm/lib/Transforms/IPO/GlobalOpt.cpp +++ b/llvm/lib/Transforms/IPO/GlobalOpt.cpp @@ -184,7 +184,7 @@ static bool IsSafeComputationToRemove(Value *V, const TargetLibraryInfo *TLI) { /// 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(GlobalVariable *GV, +static bool CleanupPointerRootUsers(Value *V, 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(GlobalVariable *GV, SmallVector<std::pair<Instruction *, Instruction *>, 32> Dead; // Constants can't be pointers to dynamically allocated memory. - for (Value::user_iterator UI = GV->user_begin(), E = GV->user_end(); + for (Value::user_iterator UI = V->user_begin(), E = V->user_end(); UI != E;) { User *U = *UI++; if (StoreInst *SI = dyn_cast<StoreInst>(U)) { @@ -232,6 +232,9 @@ static bool CleanupPointerRootUsers(GlobalVariable *GV, 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; @@ -241,7 +244,7 @@ static bool CleanupPointerRootUsers(GlobalVariable *GV, C->destroyConstant(); // This could have invalidated UI, start over from scratch. Dead.clear(); - CleanupPointerRootUsers(GV, TLI); + CleanupPointerRootUsers(V, TLI); return true; } } @@ -391,6 +394,22 @@ 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) { @@ -409,7 +428,7 @@ static bool isSafeSROAElementUse(Value *V) { return SI->getOperand(0) != V; // Otherwise, it must be a GEP. Check it and its users are safe to SRA. - return isa<GetElementPtrInst>(I) && isSafeSROAGEP(I); + return isa<GetElementPtrInst>(I) && isSafeSubSROAGEP(I); } /// Look at all uses of the global and decide whether it is safe for us to diff --git a/llvm/test/Transforms/GlobalOpt/globalsra-multigep.ll b/llvm/test/Transforms/GlobalOpt/globalsra-multigep.ll index 87a8486d881..c32a620c476 100644 --- a/llvm/test/Transforms/GlobalOpt/globalsra-multigep.ll +++ b/llvm/test/Transforms/GlobalOpt/globalsra-multigep.ll @@ -4,13 +4,20 @@ target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" 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 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] }> +; 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 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 + + } diff --git a/llvm/test/Transforms/GlobalOpt/globalsra-struct.ll b/llvm/test/Transforms/GlobalOpt/globalsra-struct.ll new file mode 100644 index 00000000000..957fba81068 --- /dev/null +++ b/llvm/test/Transforms/GlobalOpt/globalsra-struct.ll @@ -0,0 +1,18 @@ +; RUN: opt < %s -globalopt -S | FileCheck %s + +%struct.Expr = type { [1 x i32], i32 } + +@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 +} |
