[llvm] 8098f25 - [LV] Use Legal::isUniform to detect uniform pointers.

[Florian Hahn via llvm-commits]

Author: Florian Hahn
Date: 2023-05-30T16:42:55+01:00
New Revision: 8098f2577efa4e0319a8252d8f8d7c382aa71986

URL: https://github.com/llvm/llvm-project/commit/8098f2577efa4e0319a8252d8f8d7c382aa71986
DIFF: https://github.com/llvm/llvm-project/commit/8098f2577efa4e0319a8252d8f8d7c382aa71986.diff

LOG: [LV] Use Legal::isUniform to detect uniform pointers.

Update collectLoopUniforms to identify uniform pointers using
Legal::isUniform. This is more powerful and  brings pointer
classification here in sync with setCostBasedWideningDecision
which uses isUniformMemOp. The existing mis-match in reasoning
can causes crashes due to D134460, which is fixed by this patch.

Fixes https://github.com/llvm/llvm-project/issues/60831.

Reviewed By: Ayal

Differential Revision: https://reviews.llvm.org/D150991

Added: 
    

Modified: 
    llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
    llvm/test/Transforms/LoopVectorize/AArch64/pr60831-sve-inv-store-crash.ll
    llvm/test/Transforms/LoopVectorize/skeleton-lcssa-crash.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 0a99ccb5df373..9c5caaddb4852 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -4703,7 +4703,8 @@ void LoopVectorizationCostModel::collectLoopUniforms(ElementCount VF) {
   auto isVectorizedMemAccessUse = [&](Instruction *I, Value *Ptr) -> bool {
     if (isa<StoreInst>(I) && I->getOperand(0) == Ptr)
       return false;
-    return getLoadStorePointerOperand(I) == Ptr && isUniformDecision(I, VF);
+    return getLoadStorePointerOperand(I) == Ptr &&
+           (isUniformDecision(I, VF) || Legal->isUniform(Ptr));
   };
 
   // Holds a list of values which are known to have at least one uniform use.
@@ -4749,10 +4750,8 @@ void LoopVectorizationCostModel::collectLoopUniforms(ElementCount VF) {
       if (isUniformMemOpUse(&I))
         addToWorklistIfAllowed(&I);
 
-      if (isVectorizedMemAccessUse(&I, Ptr)) {
-        assert(isUniformDecision(&I, VF) && "consistency check");
+      if (isVectorizedMemAccessUse(&I, Ptr))
         HasUniformUse.insert(Ptr);
-      }
     }
 
   // Add to the worklist any operands which have *only* uniform (e.g. lane 0

diff  --git a/llvm/test/Transforms/LoopVectorize/AArch64/pr60831-sve-inv-store-crash.ll b/llvm/test/Transforms/LoopVectorize/AArch64/pr60831-sve-inv-store-crash.ll
index cff60b10d0187..9526dd11cd6da 100644
--- a/llvm/test/Transforms/LoopVectorize/AArch64/pr60831-sve-inv-store-crash.ll
+++ b/llvm/test/Transforms/LoopVectorize/AArch64/pr60831-sve-inv-store-crash.ll
@@ -3,9 +3,6 @@
 
 target triple = "aarch64-unknown-linux-gnu"
 
-; REQUIRES: asserts
-; XFAIL: *
-
 ; Test cases for PR60831.
 
 define void @test_invar_gep(ptr %dst) #0 {

diff  --git a/llvm/test/Transforms/LoopVectorize/skeleton-lcssa-crash.ll b/llvm/test/Transforms/LoopVectorize/skeleton-lcssa-crash.ll
index e5d00b35f11ed..db5a7105fd8c4 100644
--- a/llvm/test/Transforms/LoopVectorize/skeleton-lcssa-crash.ll
+++ b/llvm/test/Transforms/LoopVectorize/skeleton-lcssa-crash.ll
@@ -50,13 +50,11 @@ define i16 @test(ptr %arg, i64 %N) {
 ; CHECK-NEXT:    [[TMP6:%.*]] = getelementptr inbounds i16, ptr [[TMP5]], i32 0
 ; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <2 x i16>, ptr [[TMP6]], align 2, !alias.scope !0
 ; CHECK-NEXT:    [[TMP7:%.*]] = getelementptr inbounds i16, ptr [[L_2]], i64 0
-; CHECK-NEXT:    [[TMP8:%.*]] = extractelement <2 x i16> [[WIDE_LOAD]], i32 0
+; CHECK-NEXT:    [[TMP8:%.*]] = extractelement <2 x i16> [[WIDE_LOAD]], i32 1
 ; CHECK-NEXT:    store i16 [[TMP8]], ptr [[TMP7]], align 2, !alias.scope !3, !noalias !0
-; CHECK-NEXT:    [[TMP9:%.*]] = extractelement <2 x i16> [[WIDE_LOAD]], i32 1
-; CHECK-NEXT:    store i16 [[TMP9]], ptr [[TMP7]], align 2, !alias.scope !3, !noalias !0
 ; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 2
-; CHECK-NEXT:    [[TMP10:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
-; CHECK-NEXT:    br i1 [[TMP10]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP5:![0-9]+]]
+; CHECK-NEXT:    [[TMP9:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-NEXT:    br i1 [[TMP9]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP5:![0-9]+]]
 ; CHECK:       middle.block:
 ; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[TMP0]], [[N_VEC]]
 ; CHECK-NEXT:    br i1 [[CMP_N]], label [[EXIT_LOOPEXIT:%.*]], label [[SCALAR_PH]]