[PATCH] D82998: [BasicAA] Enable -basic-aa-recphi by default

[Dave Green via Phabricator via llvm-commits]

dmgreen created this revision.
dmgreen added reviewers: hfinkel, efriedma, fhahn, tobiasvk.
Herald added a subscriber: hiraditya.
Herald added a project: LLVM.
dmgreen added a parent revision: D82987: [BasicAA] Fix recursive phi MustAlias calculations.
dmgreen updated this revision to Diff 274933.
dmgreen added a comment.

Fixup basic-aa argument.


This option was added a while back, to help improve AA around pointer phi loops. It looks for phi(gep(phi, const), x) loops, checking if x can then prove more precise aliasing info. It should not have an effect on compile time, only adding a couple of extra checks to existing code.

Requires D82987 <https://reviews.llvm.org/D82987>.


https://reviews.llvm.org/D82998

Files:
  llvm/lib/Analysis/BasicAliasAnalysis.cpp
  llvm/test/Analysis/BasicAA/phi-loop.ll
  llvm/test/Analysis/BasicAA/recphi.ll


Index: llvm/test/Analysis/BasicAA/recphi.ll
===================================================================
--- llvm/test/Analysis/BasicAA/recphi.ll
+++ llvm/test/Analysis/BasicAA/recphi.ll
@@ -1,4 +1,4 @@
-; RUN: opt < %s -basic-aa -aa-eval -print-all-alias-modref-info -basic-aa-recphi -disable-output 2>&1 | FileCheck %s
+; RUN: opt < %s -basic-aa -aa-eval -print-all-alias-modref-info -disable-output 2>&1 | FileCheck %s
 
 ; CHECK-LABEL: Function: simple: 5 pointers, 0 call sites
 ; CHECK:         NoAlias:      float* %src1, float* %src2
Index: llvm/test/Analysis/BasicAA/phi-loop.ll
===================================================================
--- llvm/test/Analysis/BasicAA/phi-loop.ll
+++ llvm/test/Analysis/BasicAA/phi-loop.ll
@@ -1,4 +1,4 @@
-; RUN: opt < %s -basic-aa -basic-aa-recphi=1 -gvn -S | FileCheck %s
+; RUN: opt < %s -basic-aa -gvn -S | FileCheck %s
 ;
 ; Check that section->word_ofs doesn't get reloaded in every iteration of the
 ; for loop.
Index: llvm/lib/Analysis/BasicAliasAnalysis.cpp
===================================================================
--- llvm/lib/Analysis/BasicAliasAnalysis.cpp
+++ llvm/lib/Analysis/BasicAliasAnalysis.cpp
@@ -66,7 +66,7 @@
 
 /// Enable analysis of recursive PHI nodes.
 static cl::opt<bool> EnableRecPhiAnalysis("basic-aa-recphi", cl::Hidden,
-                                          cl::init(false));
+                                          cl::init(true));
 
 /// By default, even on 32-bit architectures we use 64-bit integers for
 /// calculations. This will allow us to more-aggressively decompose indexing


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