[llvm] 5a406b6 - [Attributor][FIX] Stores capture, even for readonly functions

[Johannes Doerfert via llvm-commits]

Author: Johannes Doerfert
Date: 2023-08-11T14:17:33-07:00
New Revision: 5a406b63e9d70225cd56fd5c3b791e78f4aed3cc

URL: https://github.com/llvm/llvm-project/commit/5a406b63e9d70225cd56fd5c3b791e78f4aed3cc
DIFF: https://github.com/llvm/llvm-project/commit/5a406b63e9d70225cd56fd5c3b791e78f4aed3cc.diff

LOG: [Attributor][FIX] Stores capture, even for readonly functions

If we end up visiting a store use, we couldn't follow to the "reloads".
The capture effect of a store is more than memory as the reloads are
unknown.

Fixes: https://github.com/llvm/llvm-project/issues/64613

Added: 
    

Modified: 
    llvm/lib/Transforms/IPO/AttributorAttributes.cpp
    llvm/test/Transforms/Attributor/nocapture-2.ll

Removed: 
    


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diff  --git a/llvm/lib/Transforms/IPO/AttributorAttributes.cpp b/llvm/lib/Transforms/IPO/AttributorAttributes.cpp
index c5259c1e312ae0..e4b79acf3f02e3 100644
--- a/llvm/lib/Transforms/IPO/AttributorAttributes.cpp
+++ b/llvm/lib/Transforms/IPO/AttributorAttributes.cpp
@@ -5885,8 +5885,8 @@ struct AANoCaptureImpl : public AANoCapture {
     // For stores we already checked if we can follow them, if they make it
     // here we give up.
     if (isa<StoreInst>(UInst))
-      return isCapturedIn(State, /* Memory */ true, /* Integer */ false,
-                          /* Return */ false);
+      return isCapturedIn(State, /* Memory */ true, /* Integer */ true,
+                          /* Return */ true);
 
     // Explicitly catch return instructions.
     if (isa<ReturnInst>(UInst)) {

diff  --git a/llvm/test/Transforms/Attributor/nocapture-2.ll b/llvm/test/Transforms/Attributor/nocapture-2.ll
index 1a7fee28188acc..1e5e9da19909f6 100644
--- a/llvm/test/Transforms/Attributor/nocapture-2.ll
+++ b/llvm/test/Transforms/Attributor/nocapture-2.ll
@@ -756,7 +756,7 @@ define ptr @b64613_a(ptr noundef %p) {
 define ptr @b64613_b(ptr noundef %p, i32 %i) {
 ; TUNIT: Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(none)
 ; TUNIT-LABEL: define ptr @b64613_b
-; TUNIT-SAME: (ptr nocapture nofree noundef [[P:%.*]], i32 [[I:%.*]]) #[[ATTR11]] {
+; TUNIT-SAME: (ptr nofree noundef [[P:%.*]], i32 [[I:%.*]]) #[[ATTR11]] {
 ; TUNIT-NEXT:    [[P_ADDR:%.*]] = alloca <2 x ptr>, align 1
 ; TUNIT-NEXT:    [[G:%.*]] = getelementptr i8, ptr [[P_ADDR]], i32 [[I]]
 ; TUNIT-NEXT:    store ptr [[P]], ptr [[G]], align 1
@@ -765,7 +765,7 @@ define ptr @b64613_b(ptr noundef %p, i32 %i) {
 ;
 ; CGSCC: Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(none)
 ; CGSCC-LABEL: define ptr @b64613_b
-; CGSCC-SAME: (ptr nocapture nofree noundef [[P:%.*]], i32 [[I:%.*]]) #[[ATTR12]] {
+; CGSCC-SAME: (ptr nofree noundef [[P:%.*]], i32 [[I:%.*]]) #[[ATTR12]] {
 ; CGSCC-NEXT:    [[P_ADDR:%.*]] = alloca <2 x ptr>, align 1
 ; CGSCC-NEXT:    [[G:%.*]] = getelementptr i8, ptr [[P_ADDR]], i32 [[I]]
 ; CGSCC-NEXT:    store ptr [[P]], ptr [[G]], align 1