GlobalOpt: Improve addrspacecast handling

[arsenm]

Summary

Handle addrspacecast when looking at uses.

[aeubanks]

lgtm

[arsenm]

6923a67db8439616ffb48b215dca6cd0674b43f8

llvm/lib/Transforms/IPO/GlobalOpt.cpp

if (isa<LoadInst>(U)) {
         return false;  // Not calling the ptr
       }
     } else if (const InvokeInst *II = dyn_cast<InvokeInst>(U)) {
       if (II->getCalledOperand() != V) {
         return false;  // Not calling the ptr
       }
     } else if (const BitCastInst *CI = dyn_cast<BitCastInst>(U)) {
       if (!AllUsesOfValueWillTrapIfNull(CI, PHIs)) return false;
+    } else if (const AddrSpaceCastInst *CI = dyn_cast<AddrSpaceCastInst>(U)) {
+      if (!AllUsesOfValueWillTrapIfNull(CI, PHIs))
+        return false;
     } else if (const GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(U)) {
       if (!AllUsesOfValueWillTrapIfNull(GEPI, PHIs)) return false;
     } else if (const PHINode *PN = dyn_cast<PHINode>(U)) {
       // If we've already seen this phi node, ignore it, it has already been
       // checked.
       if (PHIs.insert(PN).second && !AllUsesOfValueWillTrapIfNull(PN, PHIs))
         return false;
     } else if (isa<ICmpInst>(U) &&
for (User *GlobalUser : llvm::make_early_inc_range(GV->users())) {
     } else {
       AllNonStoreUsesGone = false;
 
       // If we get here we could have other crazy uses that are transitively
       // loaded.
       assert((isa<PHINode>(GlobalUser) || isa<SelectInst>(GlobalUser) ||
               isa<ConstantExpr>(GlobalUser) || isa<CmpInst>(GlobalUser) ||
               isa<BitCastInst>(GlobalUser) ||
-              isa<GetElementPtrInst>(GlobalUser)) &&
+              isa<GetElementPtrInst>(GlobalUser) ||
+              isa<AddrSpaceCastInst>(GlobalUser)) &&
              "Only expect load and stores!");
     }
   }
 
   if (Changed) {
     LLVM_DEBUG(dbgs() << "OPTIMIZED LOADS FROM STORED ONCE POINTER: " << *GV
                       << "\n");
     ++NumGlobUses;

llvm/test/Transforms/GlobalOpt/load-store-global.ll

define void @qux() nounwind {
   store ptr inttoptr (i64 1 to ptr), ptr @a, align 8
   %l = load ptr, ptr @a, align 8
   ret void
 ; CHECK-LABEL: @qux(
 ; CHECK-NOT: store
 ; CHECK-NOT: load
 }
 
+@addrspacecast_a = internal global ptr null
+
+define void @addrspacecast_user() {
+; CHECK-LABEL: @addrspacecast_user
+; CHECK-NOT: store
+; CHECK-NOT: load
+  %g = addrspacecast ptr @addrspacecast_a to ptr addrspace(1)
+  store ptr inttoptr (i64 1 to ptr), ptr @addrspacecast_a, align 8
+  %l = load ptr, ptr @addrspacecast_a, align 8
+  ret void
+}

llvm/test/Transforms/GlobalOpt/malloc-promote-addrspacecast.ll

 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals
 ; RUN: opt -S -passes=globalopt < %s | FileCheck %s
 target datalayout = "E-p:64:64:64-a0:0:8-f32:32:32-f64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-v64:64:64-v128:128:128"
 
 declare noalias ptr @malloc(i64) allockind("alloc,uninitialized") allocsize(0)
 
 @G = internal global ptr null
 
-;.
-; CHECK: @[[G:[a-zA-Z0-9_$"\\.-]+]] = internal unnamed_addr global ptr null
-;.
 define void @init() {
 ; CHECK-LABEL: @init(
-; CHECK-NEXT:    [[MALLOCCALL:%.*]] = tail call ptr @malloc(i64 4)
-; CHECK-NEXT:    store ptr [[MALLOCCALL]], ptr @G, align 8
-; CHECK-NEXT:    [[GV:%.*]] = load ptr, ptr @G, align 8
-; CHECK-NEXT:    [[ADDRSPACECAST:%.*]] = addrspacecast ptr [[GV]] to ptr addrspace(1)
-; CHECK-NEXT:    store i32 20, ptr addrspace(1) [[ADDRSPACECAST]], align 4
 ; CHECK-NEXT:    ret void
 ;
   %malloccall = tail call ptr @malloc(i64 4)
   store ptr %malloccall, ptr @G
   %GV = load ptr, ptr @G
   %addrspacecast = addrspacecast ptr %GV to ptr addrspace(1)
   store i32 20, ptr addrspace(1) %addrspacecast
   ret void
 }
 
 define i32 @get() {
 ; CHECK-LABEL: @get(
-; CHECK-NEXT:    [[GV:%.*]] = load ptr, ptr @G, align 8
-; CHECK-NEXT:    [[V:%.*]] = load i32, ptr [[GV]], align 4
-; CHECK-NEXT:    ret i32 [[V]]
+; CHECK-NEXT:    ret i32 20
 ;
   %GV = load ptr, ptr @G
   %V = load i32, ptr %GV
   ret i32 %V
 }
 
 define void @foo(i64 %Size) nounwind noinline #0 {
 ; CHECK-LABEL: @foo(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[TMP0:%.*]] = load ptr, ptr @G, align 4
 ; CHECK-NEXT:    ret void
 ;
 entry:
   %0 = load ptr, ptr @G, align 4
   ret void
 }
 
 attributes #0 = { null_pointer_is_valid }
 
 ;.
-; CHECK: attributes #[[ATTR0:[0-9]+]] = { allockind("alloc,uninitialized") allocsize(0) }
-; CHECK: attributes #[[ATTR1:[0-9]+]] = { noinline nounwind null_pointer_is_valid }
+; CHECK: attributes #[[ATTR0:[0-9]+]] = { noinline nounwind null_pointer_is_valid }
 ;.