[PATCH] D99737: Infer dereferenceability from malloc and friends

[Philip Reames via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rGdb357891f0cf: Infer dereferenceability from malloc and friends (authored by reames).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D99737/new/

https://reviews.llvm.org/D99737

Files:
  llvm/lib/Analysis/Loads.cpp
  llvm/test/Transforms/LICM/hoist-alloc.ll


Index: llvm/test/Transforms/LICM/hoist-alloc.ll
===================================================================
--- llvm/test/Transforms/LICM/hoist-alloc.ll
+++ llvm/test/Transforms/LICM/hoist-alloc.ll
@@ -130,7 +130,8 @@
   ret i8 %res
 }
 
-; TODO: We can hoist the load in this case.
+; TODO: We can hoist the load in this case, but only once we have
+; some form of context sensitive free analysis.
 define i8 @test_hoist_malloc() {
 ; CHECK-LABEL: @test_hoist_malloc(
 ; CHECK-NEXT:  entry:
@@ -171,18 +172,17 @@
   ret i8 %res
 }
 
-; TODO: We can hoist the load in this case.
-define i8 @test_hoist_malloc_leak() {
+define i8 @test_hoist_malloc_leak() nofree nosync {
 ; CHECK-LABEL: @test_hoist_malloc_leak(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[A_RAW:%.*]] = call nonnull i8* @malloc(i64 32)
 ; CHECK-NEXT:    call void @init(i8* [[A_RAW]])
 ; CHECK-NEXT:    [[ADDR:%.*]] = getelementptr i8, i8* [[A_RAW]], i32 31
+; CHECK-NEXT:    [[RES:%.*]] = load i8, i8* [[ADDR]], align 1
 ; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
 ; CHECK:       for.body:
 ; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ [[IV_NEXT:%.*]], [[FOR_BODY]] ], [ 0, [[ENTRY:%.*]] ]
 ; CHECK-NEXT:    call void @unknown()
-; CHECK-NEXT:    [[RES:%.*]] = load i8, i8* [[ADDR]], align 1
 ; CHECK-NEXT:    call void @use(i8 [[RES]])
 ; CHECK-NEXT:    [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
 ; CHECK-NEXT:    [[EXITCOND:%.*]] = icmp eq i64 [[IV_NEXT]], 200
Index: llvm/lib/Analysis/Loads.cpp
===================================================================
--- llvm/lib/Analysis/Loads.cpp
+++ llvm/lib/Analysis/Loads.cpp
@@ -162,8 +162,7 @@
     Opts.RoundToAlign = false;
     Opts.NullIsUnknownSize = true;
     uint64_t ObjSize;
-    // TODO: Plumb through TLI so that malloc routines and such work.
-    if (getObjectSize(V, ObjSize, DL, nullptr, Opts)) {
+    if (getObjectSize(V, ObjSize, DL, TLI, Opts)) {
       APInt KnownDerefBytes(Size.getBitWidth(), ObjSize);
       if (KnownDerefBytes.getBoolValue() && KnownDerefBytes.uge(Size) &&
           isKnownNonZero(V, DL, 0, nullptr, CtxI, DT) && !V->canBeFreed()) {


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