[PATCH] D109823: [GlobalOpt] Do not shrink global to bool for an unfavorable AS

[Christudasan Devadasan via Phabricator via llvm-commits]

cdevadas updated this revision to Diff 372751.
cdevadas added a comment.

Fixed the lit test to have only one check pattern.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D109823/new/

https://reviews.llvm.org/D109823

Files:
  llvm/lib/Transforms/IPO/GlobalOpt.cpp
  llvm/test/Transforms/GlobalOpt/shrink-global-to-bool.ll


Index: llvm/test/Transforms/GlobalOpt/shrink-global-to-bool.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/GlobalOpt/shrink-global-to-bool.ll
@@ -0,0 +1,41 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -passes=globalopt --mtriple=x86_64-unknown-linux-gnu < %s -S | FileCheck %s
+; RUN: opt -passes=globalopt --mtriple=amdgcn-amd-amdhsa < %s -S | FileCheck %s
+; REQUIRES: amdgpu-registered-target
+
+ at gvar = internal unnamed_addr global i32 undef
+ at lvar = internal unnamed_addr addrspace(3) global i32 undef
+
+; Should optimize @gvar.
+; CHECK-NOT: @gvar
+
+; Negative test for AS(3). Skip shrink global to bool optimization.
+; CHECK: @lvar = internal unnamed_addr addrspace(3) global i32 undef
+
+define void @test_global_var() {
+; CHECK-LABEL: @test_global_var(
+; CHECK:    store volatile i32 10, i32* undef, align 4
+;
+entry:
+  store i32 10, i32* @gvar
+  br label %exit
+exit:
+  %ld = load i32, i32* @gvar
+  store volatile i32 %ld, i32* undef
+  ret void
+}
+
+define void @test_lds_var() {
+; CHECK-LABEL: @test_lds_var(
+; CHECK:    store i32 10, i32 addrspace(3)* @lvar, align 4
+; CHECK:    [[LD:%.*]] = load i32, i32 addrspace(3)* @lvar, align 4
+; CHECK:    store volatile i32 [[LD]], i32* undef, align 4
+;
+entry:
+  store i32 10, i32 addrspace(3)* @lvar
+  br label %exit
+exit:
+  %ld = load i32, i32 addrspace(3)* @lvar
+  store volatile i32 %ld, i32* undef
+  ret void
+}
Index: llvm/lib/Transforms/IPO/GlobalOpt.cpp
===================================================================
--- llvm/lib/Transforms/IPO/GlobalOpt.cpp
+++ llvm/lib/Transforms/IPO/GlobalOpt.cpp
@@ -1612,6 +1612,9 @@
 
     Function &StoreFn =
         const_cast<Function &>(*GS.StoredOnceStore->getFunction());
+    bool CanHaveNonUndefGlobalInitializer =
+        GetTTI(StoreFn).canHaveNonUndefGlobalInitializerInAddressSpace(
+            GV->getType()->getAddressSpace());
     // If the initial value for the global was an undef value, and if only
     // one other value was stored into it, we can just change the
     // initializer to be the stored value, then delete all stores to the
@@ -1621,8 +1624,7 @@
     // shared memory (AS 3).
     if (SOVConstant && SOVConstant->getType() == GV->getValueType() &&
         isa<UndefValue>(GV->getInitializer()) &&
-        GetTTI(StoreFn).canHaveNonUndefGlobalInitializerInAddressSpace(
-            GV->getType()->getAddressSpace())) {
+        CanHaveNonUndefGlobalInitializer) {
       // Change the initial value here.
       GV->setInitializer(SOVConstant);
 
@@ -1645,8 +1647,10 @@
       return true;
 
     // Otherwise, if the global was not a boolean, we can shrink it to be a
-    // boolean.
-    if (SOVConstant && GS.Ordering == AtomicOrdering::NotAtomic) {
+    // boolean. Skip this optimization for AS that doesn't allow an initializer.
+    if (SOVConstant && GS.Ordering == AtomicOrdering::NotAtomic &&
+        (!isa<UndefValue>(GV->getInitializer()) ||
+         CanHaveNonUndefGlobalInitializer)) {
       if (TryToShrinkGlobalToBoolean(GV, SOVConstant)) {
         ++NumShrunkToBool;
         return true;


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