[PATCH] D154001: [ScalarEvolution] Analyze ranges for heap allocations

[Arthur Eubanks via Phabricator via llvm-commits]

aeubanks created this revision.
aeubanks added a reviewer: nikic.
Herald added subscribers: StephenFan, hiraditya.
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Followup to D153624 <https://reviews.llvm.org/D153624>. Allows for better exit count calculations for loops checking heap allocations against null.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D154001

Files:
  llvm/lib/Analysis/ScalarEvolution.cpp
  llvm/test/Analysis/ScalarEvolution/malloc.ll


Index: llvm/test/Analysis/ScalarEvolution/malloc.ll
===================================================================
--- llvm/test/Analysis/ScalarEvolution/malloc.ll
+++ llvm/test/Analysis/ScalarEvolution/malloc.ll
@@ -5,7 +5,7 @@
 ; CHECK-LABEL: 'f'
 ; CHECK-NEXT:  Classifying expressions for: @f
 ; CHECK-NEXT:    %alloc = tail call dereferenceable(64) ptr @malloc(i64 64)
-; CHECK-NEXT:    --> %alloc U: full-set S: full-set
+; CHECK-NEXT:    --> %alloc U: [1,-64) S: full-set
 ; CHECK-NEXT:  Determining loop execution counts for: @f
 ;
   %alloc = tail call dereferenceable(64) ptr @malloc(i64 64)
@@ -16,7 +16,7 @@
 ; CHECK-LABEL: 'f2'
 ; CHECK-NEXT:  Classifying expressions for: @f2
 ; CHECK-NEXT:    %alloc = tail call dereferenceable_or_null(64) ptr @malloc(i64 64)
-; CHECK-NEXT:    --> %alloc U: full-set S: full-set
+; CHECK-NEXT:    --> %alloc U: [0,-64) S: full-set
 ; CHECK-NEXT:  Determining loop execution counts for: @f2
 ;
   %alloc = tail call dereferenceable_or_null(64) ptr @malloc(i64 64)
Index: llvm/lib/Analysis/ScalarEvolution.cpp
===================================================================
--- llvm/lib/Analysis/ScalarEvolution.cpp
+++ llvm/lib/Analysis/ScalarEvolution.cpp
@@ -6816,7 +6816,8 @@
       Opts.RoundToAlign = false;
       Opts.NullIsUnknownSize = true;
       uint64_t ObjSize;
-      if ((isa<GlobalVariable>(V) || isa<AllocaInst>(V)) &&
+      if ((isa<GlobalVariable>(V) || isa<AllocaInst>(V) ||
+           isAllocationFn(V, &TLI)) &&
           getObjectSize(V, ObjSize, DL, &TLI, Opts) && ObjSize > 1) {
         // The highest address the object can start is ObjSize bytes before the
         // end (unsigned max value). If this value is not a multiple of the


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