[llvm] 082c81a - [LV] Properly extend versioned constant strides.

[Florian Hahn via llvm-commits]

Author: Florian Hahn
Date: 2024-05-07T21:31:42+01:00
New Revision: 082c81ae4ab9db6bb0acd52098288223dd58501a

URL: https://github.com/llvm/llvm-project/commit/082c81ae4ab9db6bb0acd52098288223dd58501a
DIFF: https://github.com/llvm/llvm-project/commit/082c81ae4ab9db6bb0acd52098288223dd58501a.diff

LOG: [LV] Properly extend versioned constant strides.

We only version unknown strides to 1. If the original type is i1, then
the sign of the extension matters. Properly extend the stride value
before replacing it.

Fixes https://github.com/llvm/llvm-project/issues/91369.

Added: 
    

Modified: 
    llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
    llvm/test/Transforms/LoopVectorize/version-stride-with-integer-casts.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 3be0102bea3e3..261933966b74b 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -8841,8 +8841,10 @@ LoopVectorizationPlanner::tryToBuildVPlanWithVPRecipes(VFRange &Range) {
       VPValue *StrideVPV = Plan->getLiveIn(U);
       if (!StrideVPV)
         continue;
-      VPValue *CI = Plan->getOrAddLiveIn(ConstantInt::get(
-          U->getType(), ScevStride->getAPInt().getSExtValue()));
+      unsigned BW = U->getType()->getScalarSizeInBits();
+      APInt C = isa<SExtInst>(U) ? ScevStride->getAPInt().sext(BW)
+                                 : ScevStride->getAPInt().zext(BW);
+      VPValue *CI = Plan->getOrAddLiveIn(ConstantInt::get(U->getType(), C));
       StrideVPV->replaceAllUsesWith(CI);
     }
   }

diff  --git a/llvm/test/Transforms/LoopVectorize/version-stride-with-integer-casts.ll b/llvm/test/Transforms/LoopVectorize/version-stride-with-integer-casts.ll
index 45745f85de95c..45596169da3cc 100644
--- a/llvm/test/Transforms/LoopVectorize/version-stride-with-integer-casts.ll
+++ b/llvm/test/Transforms/LoopVectorize/version-stride-with-integer-casts.ll
@@ -415,7 +415,6 @@ exit:
 
 ; Test case to make sure that uses of versioned strides of type i1 are properly
 ; extended. From https://github.com/llvm/llvm-project/issues/91369.
-; FIXME: Currently miscompiled.
 define void @zext_of_i1_stride(i1 %g, ptr %dst) mustprogress {
 ; CHECK-LABEL: define void @zext_of_i1_stride(
 ; CHECK-SAME: i1 [[G:%.*]], ptr [[DST:%.*]]) #[[ATTR0:[0-9]+]] {
@@ -441,7 +440,7 @@ define void @zext_of_i1_stride(i1 %g, ptr %dst) mustprogress {
 ; CHECK-NEXT:    [[TMP3:%.*]] = add i64 [[OFFSET_IDX]], [[TMP2]]
 ; CHECK-NEXT:    [[TMP4:%.*]] = getelementptr inbounds i16, ptr [[DST]], i64 [[TMP3]]
 ; CHECK-NEXT:    [[TMP5:%.*]] = getelementptr inbounds i16, ptr [[TMP4]], i32 0
-; CHECK-NEXT:    store <4 x i16> <i16 -1, i16 -1, i16 -1, i16 -1>, ptr [[TMP5]], align 2
+; CHECK-NEXT:    store <4 x i16> <i16 1, i16 1, i16 1, i16 1>, ptr [[TMP5]], align 2
 ; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
 ; CHECK-NEXT:    [[TMP6:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
 ; CHECK-NEXT:    br i1 [[TMP6]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP12:![0-9]+]]