[llvm] [AssumptionCache] Track GlobalValues as affected values. (PR #65425)

[Tyler Lanphear via llvm-commits]

https://github.com/tylanphear created https://github.com/llvm/llvm-project/pull/65425:

Fixes a corner case of the analysis: previously GlobalValues could be affected by assumptions, but were not tracked within AffectedValues. This patch allows assumptions which affect a given GlobalValue to be looked up via `assumptionsFor()`.

A small update to llvm/test/Analysis/ScalarEvolution/ranges.ll was necessary due to knowledge about a global value now being propagated from AssumptionCache -> ValueTracking -> ScalarEvolution.

>From 9efedae519feae8f36cb981b41706d3f22075c61 Mon Sep 17 00:00:00 2001
From: Tyler Lanphear <tyler.lanphear at intel.com>
Date: Fri, 1 Sep 2023 15:50:25 -0700
Subject: [PATCH] [AssumptionCache] Track GlobalValues as affected values.

Fixes a corner case of the analysis: previously GlobalValues could be
affected by assumptions, but were not tracked within AffectedValues.
This patch allows assumptions which affect a given GlobalValue to be
looked up via `assumptionsFor()`.

A small update to llvm/test/Analysis/ScalarEvolution/ranges.ll was
necessary due to knowledge about a global value now being propagated
from AssumptionCache -> ValueTracking -> ScalarEvolution.
---
 llvm/lib/Analysis/AssumptionCache.cpp        |  2 +-
 llvm/test/Analysis/AssumptionCache/basic.ll  | 11 +++++++++++
 llvm/test/Analysis/ScalarEvolution/ranges.ll |  2 +-
 3 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/Analysis/AssumptionCache.cpp b/llvm/lib/Analysis/AssumptionCache.cpp
index b439dc1e6a76d7f..b0df934501114d2 100644
--- a/llvm/lib/Analysis/AssumptionCache.cpp
+++ b/llvm/lib/Analysis/AssumptionCache.cpp
@@ -62,7 +62,7 @@ findAffectedValues(CallBase *CI, TargetTransformInfo *TTI,
 
   auto AddAffected = [&Affected](Value *V, unsigned Idx =
                                                AssumptionCache::ExprResultIdx) {
-    if (isa<Argument>(V)) {
+    if (isa<Argument>(V) || isa<GlobalValue>(V)) {
       Affected.push_back({V, Idx});
     } else if (auto *I = dyn_cast<Instruction>(V)) {
       Affected.push_back({I, Idx});
diff --git a/llvm/test/Analysis/AssumptionCache/basic.ll b/llvm/test/Analysis/AssumptionCache/basic.ll
index bd4e7b6449fb750..6056ed1a4c4576d 100644
--- a/llvm/test/Analysis/AssumptionCache/basic.ll
+++ b/llvm/test/Analysis/AssumptionCache/basic.ll
@@ -20,3 +20,14 @@ entry:
 
   ret void
 }
+
+ at G = external global i32
+define void @test2() {
+; CHECK-LABEL: Cached assumptions for function: test2
+; CHECK-NEXT: icmp ne ptr @G, null
+
+entry:
+  %cond1 = icmp ne ptr @G, null
+  call void @llvm.assume(i1 %cond1)
+  ret void
+}
diff --git a/llvm/test/Analysis/ScalarEvolution/ranges.ll b/llvm/test/Analysis/ScalarEvolution/ranges.ll
index ad11a94b3963557..d42abac1971fb08 100644
--- a/llvm/test/Analysis/ScalarEvolution/ranges.ll
+++ b/llvm/test/Analysis/ScalarEvolution/ranges.ll
@@ -29,7 +29,7 @@ define i64 @ashr_global() {
 ; CHECK-LABEL: 'ashr_global'
 ; CHECK-NEXT:  Classifying expressions for: @ashr_global
 ; CHECK-NEXT:    %ashr = ashr i64 ptrtoint (ptr @G to i64), 63
-; CHECK-NEXT:    --> %ashr U: [-1,1) S: [-1,1)
+; CHECK-NEXT:    --> %ashr U: [0,1) S: [0,1)
 ; CHECK-NEXT:  Determining loop execution counts for: @ashr_global
 ;
   %ashr = ashr i64 ptrtoint (ptr @G to i64), 63