[llvm] b98c405 - [EarlyCSE] De-Duplicate callsites with differing attrs
Noah Goldstein via llvm-commits
llvm-commits at lists.llvm.org
Fri Oct 4 08:36:42 PDT 2024
Author: Noah Goldstein
Date: 2024-10-04T10:36:28-05:00
New Revision: b98c405f954f9ef6150c655f6ffc68e377d2ac84
URL: https://github.com/llvm/llvm-project/commit/b98c405f954f9ef6150c655f6ffc68e377d2ac84
DIFF: https://github.com/llvm/llvm-project/commit/b98c405f954f9ef6150c655f6ffc68e377d2ac84.diff
LOG: [EarlyCSE] De-Duplicate callsites with differing attrs
We only do this if the attributes of the two callsites are compatible
(intersectable) which is probably not in fact necessary.
Closes #110929
Added:
Modified:
llvm/lib/Transforms/Scalar/EarlyCSE.cpp
llvm/test/Transforms/EarlyCSE/replace-calls-def-attrs.ll
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/Scalar/EarlyCSE.cpp b/llvm/lib/Transforms/Scalar/EarlyCSE.cpp
index cf11f5bc885a75..a1dbb4e1d5e75f 100644
--- a/llvm/lib/Transforms/Scalar/EarlyCSE.cpp
+++ b/llvm/lib/Transforms/Scalar/EarlyCSE.cpp
@@ -362,7 +362,7 @@ static bool isEqualImpl(SimpleValue LHS, SimpleValue RHS) {
if (LHSI->getOpcode() != RHSI->getOpcode())
return false;
- if (LHSI->isIdenticalToWhenDefined(RHSI)) {
+ if (LHSI->isIdenticalToWhenDefined(RHSI, /*IntersectAttrs=*/true)) {
// Convergent calls implicitly depend on the set of threads that is
// currently executing, so conservatively return false if they are in
//
diff erent basic blocks.
@@ -551,7 +551,7 @@ bool DenseMapInfo<CallValue>::isEqual(CallValue LHS, CallValue RHS) {
if (LHSI->isConvergent() && LHSI->getParent() != RHSI->getParent())
return false;
- return LHSI->isIdenticalTo(RHSI);
+ return LHSI->isIdenticalToWhenDefined(RHSI, /*IntersectAttrs=*/true);
}
//===----------------------------------------------------------------------===//
@@ -1307,6 +1307,23 @@ static void combineIRFlags(Instruction &From, Value *To) {
(I->hasPoisonGeneratingFlags() && !programUndefinedIfPoison(I)))
I->andIRFlags(&From);
}
+ if (isa<CallBase>(&From) && isa<CallBase>(To)) {
+ // NB: Intersection of attrs between InVal.first and Inst is overly
+ // conservative. Since we only CSE readonly functions that have the same
+ // memory state, we can preserve (or possibly in some cases combine)
+ // more attributes. Likewise this implies when checking equality of
+ // callsite for CSEing, we can probably ignore more attributes.
+ // Generally poison generating attributes need to be handled with more
+ // care as they can create *new* UB if preserved/combined and violated.
+ // Attributes that imply immediate UB on the other hand would have been
+ // violated either way.
+ bool Success =
+ cast<CallBase>(To)->tryIntersectAttributes(cast<CallBase>(&From));
+ assert(Success && "Failed to intersect attributes in callsites that "
+ "passed identical check");
+ // For NDEBUG Compile.
+ (void)Success;
+ }
}
bool EarlyCSE::overridingStores(const ParseMemoryInst &Earlier,
@@ -1632,6 +1649,7 @@ bool EarlyCSE::processNode(DomTreeNode *Node) {
LLVM_DEBUG(dbgs() << "Skipping due to debug counter\n");
continue;
}
+ combineIRFlags(Inst, InVal.first);
if (!Inst.use_empty())
Inst.replaceAllUsesWith(InVal.first);
salvageKnowledge(&Inst, &AC);
diff --git a/llvm/test/Transforms/EarlyCSE/replace-calls-def-attrs.ll b/llvm/test/Transforms/EarlyCSE/replace-calls-def-attrs.ll
index 19560080744a1f..2adaf1c7b67a04 100644
--- a/llvm/test/Transforms/EarlyCSE/replace-calls-def-attrs.ll
+++ b/llvm/test/Transforms/EarlyCSE/replace-calls-def-attrs.ll
@@ -13,9 +13,8 @@ declare i8 @buz.fp(float, float)
define i8 @same_parent_combine_
diff _attrs(i8 %x, i8 %y) {
; CHECK-LABEL: define i8 @same_parent_combine_
diff _attrs(
; CHECK-SAME: i8 [[X:%.*]], i8 [[Y:%.*]]) {
-; CHECK-NEXT: [[C2:%.*]] = call i8 @baz(i8 noundef [[X]], i8 noundef [[Y]]) #[[ATTR0:[0-9]+]]
-; CHECK-NEXT: [[C1:%.*]] = call i8 @baz(i8 [[X]], i8 noundef [[Y]]) #[[ATTR0]]
-; CHECK-NEXT: [[R:%.*]] = call i8 @buz(i8 [[C1]], i8 [[C2]])
+; CHECK-NEXT: [[C1:%.*]] = call i8 @baz(i8 [[X]], i8 noundef [[Y]]) #[[ATTR0:[0-9]+]]
+; CHECK-NEXT: [[R:%.*]] = call i8 @buz(i8 [[C1]], i8 [[C1]])
; CHECK-NEXT: ret i8 [[R]]
;
%c1 = call i8 @baz(i8 noundef %x, i8 noundef %y) readnone
@@ -28,9 +27,8 @@ define i8 @same_parent_combine_
diff _attrs(i8 %x, i8 %y) {
define i8 @same_parent_combine_
diff _attrs_needs_intersect(i8 %x, i8 %y) {
; CHECK-LABEL: define i8 @same_parent_combine_
diff _attrs_needs_intersect(
; CHECK-SAME: i8 [[X:%.*]], i8 [[Y:%.*]]) {
-; CHECK-NEXT: [[C1:%.*]] = call nonnull ptr @baz.ptr(i8 noundef [[X]], i8 noundef [[Y]]) #[[ATTR0]]
-; CHECK-NEXT: [[C0:%.*]] = call ptr @baz.ptr(i8 [[X]], i8 noundef [[Y]]) #[[ATTR0]]
-; CHECK-NEXT: [[R:%.*]] = call i8 @buz.ptr(ptr [[C0]], ptr [[C1]])
+; CHECK-NEXT: [[C1:%.*]] = call ptr @baz.ptr(i8 [[X]], i8 noundef [[Y]]) #[[ATTR0]]
+; CHECK-NEXT: [[R:%.*]] = call i8 @buz.ptr(ptr [[C1]], ptr [[C1]])
; CHECK-NEXT: ret i8 [[R]]
;
%c1 = call nonnull ptr @baz.ptr(i8 noundef %x, i8 noundef %y) readnone
@@ -43,9 +41,8 @@ define i8 @same_parent_combine_
diff _attrs_needs_intersect(i8 %x, i8 %y) {
define i8 @same_parent_combine_
diff _attrs_fmf(float %x, float %y) {
; CHECK-LABEL: define i8 @same_parent_combine_
diff _attrs_fmf(
; CHECK-SAME: float [[X:%.*]], float [[Y:%.*]]) {
-; CHECK-NEXT: [[C1:%.*]] = call nnan nsz float @baz.fp(float noundef [[X]], float noundef [[Y]]) #[[ATTR1:[0-9]+]]
-; CHECK-NEXT: [[C0:%.*]] = call nnan float @baz.fp(float [[X]], float noundef [[Y]]) #[[ATTR1]]
-; CHECK-NEXT: [[R:%.*]] = call i8 @buz.fp(float [[C0]], float [[C1]])
+; CHECK-NEXT: [[C1:%.*]] = call nnan float @baz.fp(float [[X]], float noundef [[Y]]) #[[ATTR1:[0-9]+]]
+; CHECK-NEXT: [[R:%.*]] = call i8 @buz.fp(float [[C1]], float [[C1]])
; CHECK-NEXT: ret i8 [[R]]
;
%c1 = call nnan nsz float @baz.fp(float noundef %x, float noundef %y) readonly
@@ -58,9 +55,8 @@ define i8 @same_parent_combine_
diff _attrs_fmf(float %x, float %y) {
define i8 @same_parent_combine_
diff _attrs_fmf2(float %x, float %y) {
; CHECK-LABEL: define i8 @same_parent_combine_
diff _attrs_fmf2(
; CHECK-SAME: float [[X:%.*]], float [[Y:%.*]]) {
-; CHECK-NEXT: [[C1:%.*]] = call nnan float @baz.fp(float noundef [[X]], float noundef [[Y]]) #[[ATTR0]]
-; CHECK-NEXT: [[C0:%.*]] = call nnan nsz float @baz.fp(float [[X]], float noundef [[Y]]) #[[ATTR0]]
-; CHECK-NEXT: [[R:%.*]] = call i8 @buz.fp(float [[C0]], float [[C1]])
+; CHECK-NEXT: [[C1:%.*]] = call nnan float @baz.fp(float [[X]], float noundef [[Y]]) #[[ATTR0]]
+; CHECK-NEXT: [[R:%.*]] = call i8 @buz.fp(float [[C1]], float [[C1]])
; CHECK-NEXT: ret i8 [[R]]
;
%c1 = call nnan float @baz.fp(float noundef %x, float noundef %y) readnone
@@ -73,9 +69,8 @@ define i8 @same_parent_combine_
diff _attrs_fmf2(float %x, float %y) {
define i8 @same_parent_combine_
diff _attrs_needs_intersect2(i8 %x, i8 %y) {
; CHECK-LABEL: define i8 @same_parent_combine_
diff _attrs_needs_intersect2(
; CHECK-SAME: i8 [[X:%.*]], i8 [[Y:%.*]]) {
-; CHECK-NEXT: [[C1:%.*]] = call nonnull ptr @baz.ptr(i8 noundef [[X]], i8 noundef [[Y]]) #[[ATTR1]]
-; CHECK-NEXT: [[C0:%.*]] = call ptr @baz.ptr(i8 [[X]], i8 noundef [[Y]]) #[[ATTR1]]
-; CHECK-NEXT: [[R:%.*]] = call i8 @buz.ptr(ptr [[C0]], ptr [[C1]])
+; CHECK-NEXT: [[C1:%.*]] = call ptr @baz.ptr(i8 [[X]], i8 noundef [[Y]]) #[[ATTR1]]
+; CHECK-NEXT: [[R:%.*]] = call i8 @buz.ptr(ptr [[C1]], ptr [[C1]])
; CHECK-NEXT: ret i8 [[R]]
;
%c1 = call nonnull ptr @baz.ptr(i8 noundef %x, i8 noundef %y) readonly
@@ -88,9 +83,8 @@ define i8 @same_parent_combine_
diff _attrs_needs_intersect2(i8 %x, i8 %y) {
define i8 @same_parent_combine_
diff _attrs_really_needs_intersect(i8 %x, i8 %y) {
; CHECK-LABEL: define i8 @same_parent_combine_
diff _attrs_really_needs_intersect(
; CHECK-SAME: i8 [[X:%.*]], i8 [[Y:%.*]]) {
-; CHECK-NEXT: [[C1:%.*]] = call nonnull ptr @baz.ptr(i8 noundef [[X]], i8 noundef [[Y]]) #[[ATTR1]]
-; CHECK-NEXT: [[C0:%.*]] = call ptr @baz.ptr(i8 [[X]], i8 noundef [[Y]]) #[[ATTR1]]
-; CHECK-NEXT: [[R:%.*]] = call i8 @buz.ptr(ptr [[C0]], ptr noundef [[C1]])
+; CHECK-NEXT: [[C1:%.*]] = call ptr @baz.ptr(i8 [[X]], i8 noundef [[Y]]) #[[ATTR1]]
+; CHECK-NEXT: [[R:%.*]] = call i8 @buz.ptr(ptr [[C1]], ptr noundef [[C1]])
; CHECK-NEXT: ret i8 [[R]]
;
%c1 = call nonnull ptr @baz.ptr(i8 noundef %x, i8 noundef %y) readonly
@@ -160,8 +154,7 @@ define i8 @
diff _parent_combine_
diff _attrs_preserves_return_attrs(i1 %c, i8 %x, i
; CHECK-NEXT: [[C1:%.*]] = call nonnull ptr @baz.ptr(i8 [[X]], i8 noundef [[Y]]) #[[ATTR1]]
; CHECK-NEXT: br i1 [[C]], label %[[T:.*]], label %[[F:.*]]
; CHECK: [[T]]:
-; CHECK-NEXT: [[C0:%.*]] = call nonnull ptr @baz.ptr(i8 noundef [[X]], i8 noundef [[Y]]) #[[ATTR1]]
-; CHECK-NEXT: [[R:%.*]] = call i8 @buz.ptr(ptr [[C0]], ptr noundef [[C1]])
+; CHECK-NEXT: [[R:%.*]] = call i8 @buz.ptr(ptr [[C1]], ptr noundef [[C1]])
; CHECK-NEXT: ret i8 [[R]]
; CHECK: [[F]]:
; CHECK-NEXT: ret i8 9
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