[llvm] bafab9c - [InstCombine] Fix scalable-vector bitwise select matching

[Fraser Cormack via llvm-commits]

Author: Fraser Cormack
Date: 2022-05-06T12:59:39+01:00
New Revision: bafab9c09f68190d1928a341255d50a7732443ab

URL: https://github.com/llvm/llvm-project/commit/bafab9c09f68190d1928a341255d50a7732443ab
DIFF: https://github.com/llvm/llvm-project/commit/bafab9c09f68190d1928a341255d50a7732443ab.diff

LOG: [InstCombine] Fix scalable-vector bitwise select matching

D113035 enhanced the matching of bitwise selects from vector types. This
change unfortunately introduced crashes as it tries to cast scalable
vector types to integers.

Reviewed By: spatel

Differential Revision: https://reviews.llvm.org/D124997

Added: 
    

Modified: 
    llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
    llvm/test/Transforms/InstCombine/logical-select.ll

Removed: 
    


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diff  --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index c18a48feeffcd..51dc69398cdde 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -2344,8 +2344,12 @@ Value *InstCombinerImpl::matchSelectFromAndOr(Value *A, Value *C, Value *B,
     // not create unnecessary casts if the types already match.
     Type *SelTy = A->getType();
     if (auto *VecTy = dyn_cast<VectorType>(Cond->getType())) {
+      // For a fixed or scalable vector get N from <{vscale x} N x iM>
       unsigned Elts = VecTy->getElementCount().getKnownMinValue();
-      Type *EltTy = Builder.getIntNTy(SelTy->getPrimitiveSizeInBits() / Elts);
+      // For a fixed or scalable vector, get the size in bits of N x iM; for a
+      // scalar this is just M.
+      unsigned SelEltSize = SelTy->getPrimitiveSizeInBits().getKnownMinSize();
+      Type *EltTy = Builder.getIntNTy(SelEltSize / Elts);
       SelTy = VectorType::get(EltTy, VecTy->getElementCount());
     }
     Value *BitcastC = Builder.CreateBitCast(C, SelTy);

diff  --git a/llvm/test/Transforms/InstCombine/logical-select.ll b/llvm/test/Transforms/InstCombine/logical-select.ll
index aebfbd81ab051..2d7c0688d911f 100644
--- a/llvm/test/Transforms/InstCombine/logical-select.ll
+++ b/llvm/test/Transforms/InstCombine/logical-select.ll
@@ -471,6 +471,18 @@ define <4 x i1> @vec_of_bools(<4 x i1> %a, <4 x i1> %b, <4 x i1> %c) {
   ret <4 x i1> %or
 }
 
+define <vscale x 1 x i1> @vec_of_bools_scalable(<vscale x 1 x i1> %a, <vscale x 1 x i1> %c, <vscale x 1 x i1> %d) {
+; CHECK-LABEL: @vec_of_bools_scalable(
+; CHECK-NEXT:    [[TMP1:%.*]] = select <vscale x 1 x i1> [[A:%.*]], <vscale x 1 x i1> [[C:%.*]], <vscale x 1 x i1> [[D:%.*]]
+; CHECK-NEXT:    ret <vscale x 1 x i1> [[TMP1]]
+;
+  %b = xor <vscale x 1 x i1> %a, shufflevector (<vscale x 1 x i1> insertelement (<vscale x 1 x i1> poison, i1 true, i32 0), <vscale x 1 x i1> poison, <vscale x 1 x i32> zeroinitializer)
+  %t11 = and <vscale x 1 x i1> %a, %c
+  %t12 = and <vscale x 1 x i1> %b, %d
+  %r = or <vscale x 1 x i1> %t11, %t12
+  ret <vscale x 1 x i1> %r
+}
+
 define i4 @vec_of_casted_bools(i4 %a, i4 %b, <4 x i1> %c) {
 ; CHECK-LABEL: @vec_of_casted_bools(
 ; CHECK-NEXT:    [[TMP1:%.*]] = bitcast i4 [[B:%.*]] to <4 x i1>
@@ -488,6 +500,25 @@ define i4 @vec_of_casted_bools(i4 %a, i4 %b, <4 x i1> %c) {
   ret i4 %or
 }
 
+define <vscale x 1 x i64> @vec_of_casted_bools_scalable(<vscale x 1 x i64> %a, <vscale x 1 x i64> %b, <vscale x 8 x i1> %cond) {
+; CHECK-LABEL: @vec_of_casted_bools_scalable(
+; CHECK-NEXT:    [[TMP1:%.*]] = bitcast <vscale x 1 x i64> [[A:%.*]] to <vscale x 8 x i8>
+; CHECK-NEXT:    [[TMP2:%.*]] = bitcast <vscale x 1 x i64> [[B:%.*]] to <vscale x 8 x i8>
+; CHECK-NEXT:    [[TMP3:%.*]] = select <vscale x 8 x i1> [[COND:%.*]], <vscale x 8 x i8> [[TMP1]], <vscale x 8 x i8> [[TMP2]]
+; CHECK-NEXT:    [[TMP4:%.*]] = bitcast <vscale x 8 x i8> [[TMP3]] to <vscale x 1 x i64>
+; CHECK-NEXT:    ret <vscale x 1 x i64> [[TMP4]]
+;
+  %scond = sext <vscale x 8 x i1> %cond to <vscale x 8 x i8>
+  %notcond = xor <vscale x 8 x i1> %cond, shufflevector (<vscale x 8 x i1> insertelement (<vscale x 8 x i1> poison, i1 true, i32 0), <vscale x 8 x i1> poison, <vscale x 8 x i32> zeroinitializer)
+  %snotcond = sext <vscale x 8 x i1> %notcond to <vscale x 8 x i8>
+  %bc1 = bitcast <vscale x 8 x i8> %scond to <vscale x 1 x i64>
+  %bc2 = bitcast <vscale x 8 x i8> %snotcond to <vscale x 1 x i64>
+  %and1 = and <vscale x 1 x i64> %a, %bc1
+  %and2 = and <vscale x 1 x i64> %bc2, %b
+  %or = or <vscale x 1 x i64> %and1, %and2
+  ret <vscale x 1 x i64> %or
+}
+
 ; Inverted 'and' constants mean this is a select which is canonicalized to a shuffle.
 
 define <4 x i32> @vec_sel_consts(<4 x i32> %a, <4 x i32> %b) {