[LV] Add test with reduction start values that are/may be poison/undef.

Test cases for #62565.

Author: fhahn

llvm/test/Transforms/LoopVectorize/select-reduction-start-value-may-be-undef-or-poison.ll

@@ -0,0 +1,202 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 2
+; RUN: opt -passes=loop-vectorize -force-vector-width=2 -force-vector-interleave=1 -S %s | FileCheck %s
+
+
+define i64 @pr62565_incoming_value_known_undef(i64 %a, ptr %src) {
+; CHECK-LABEL: define i64 @pr62565_incoming_value_known_undef
+; CHECK-SAME: (i64 [[A:%.*]], ptr [[SRC:%.*]]) {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br i1 false, label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
+; CHECK:       vector.ph:
+; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <2 x i64> poison, i64 [[A]], i64 0
+; CHECK-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <2 x i64> [[BROADCAST_SPLATINSERT]], <2 x i64> poison, <2 x i32> zeroinitializer
+; CHECK-NEXT:    br label [[VECTOR_BODY:%.*]]
+; CHECK:       vector.body:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i32 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[VEC_PHI:%.*]] = phi <2 x i64> [ undef, [[VECTOR_PH]] ], [ [[TMP4:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[OFFSET_IDX:%.*]] = add i32 1, [[INDEX]]
+; CHECK-NEXT:    [[TMP0:%.*]] = add i32 [[OFFSET_IDX]], 0
+; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i32, ptr [[SRC]], i32 [[TMP0]]
+; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i32, ptr [[TMP1]], i32 0
+; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <2 x i32>, ptr [[TMP2]], align 4
+; CHECK-NEXT:    [[TMP3:%.*]] = icmp eq <2 x i32> [[WIDE_LOAD]], <i32 1, i32 1>
+; CHECK-NEXT:    [[TMP4]] = select <2 x i1> [[TMP3]], <2 x i64> [[VEC_PHI]], <2 x i64> [[BROADCAST_SPLAT]]
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i32 [[INDEX]], 2
+; CHECK-NEXT:    [[TMP5:%.*]] = icmp eq i32 [[INDEX_NEXT]], 32
+; CHECK-NEXT:    br i1 [[TMP5]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
+; CHECK:       middle.block:
+; CHECK-NEXT:    [[RDX_SELECT_CMP:%.*]] = icmp ne <2 x i64> [[TMP4]], undef
+; CHECK-NEXT:    [[TMP6:%.*]] = call i1 @llvm.vector.reduce.or.v2i1(<2 x i1> [[RDX_SELECT_CMP]])
+; CHECK-NEXT:    [[RDX_SELECT:%.*]] = select i1 [[TMP6]], i64 [[A]], i64 undef
+; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i32 32, 32
+; CHECK-NEXT:    br i1 [[CMP_N]], label [[EXIT:%.*]], label [[SCALAR_PH]]
+; CHECK:       scalar.ph:
+; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i32 [ 33, [[MIDDLE_BLOCK]] ], [ 1, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i64 [ undef, [[ENTRY]] ], [ [[RDX_SELECT]], [[MIDDLE_BLOCK]] ]
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i32 [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ], [ [[ADD:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[RED:%.*]] = phi i64 [ [[BC_MERGE_RDX]], [[SCALAR_PH]] ], [ [[SELECT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[GEP:%.*]] = getelementptr inbounds i32, ptr [[SRC]], i32 [[IV]]
+; CHECK-NEXT:    [[L:%.*]] = load i32, ptr [[GEP]], align 4
+; CHECK-NEXT:    [[C:%.*]] = icmp eq i32 [[L]], 1
+; CHECK-NEXT:    [[SELECT]] = select i1 [[C]], i64 [[RED]], i64 [[A]]
+; CHECK-NEXT:    [[ADD]] = add nuw i32 [[IV]], 1
+; CHECK-NEXT:    [[EC:%.*]] = icmp eq i32 [[IV]], 32
+; CHECK-NEXT:    br i1 [[EC]], label [[EXIT]], label [[LOOP]], !llvm.loop [[LOOP3:![0-9]+]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[PHI:%.*]] = phi i64 [ [[SELECT]], [[LOOP]] ], [ [[RDX_SELECT]], [[MIDDLE_BLOCK]] ]
+; CHECK-NEXT:    ret i64 [[PHI]]
+;
+entry:
+  br label %loop
+
+loop:
+  %iv = phi i32 [ 1, %entry ], [ %add, %loop ]
+  %red = phi i64 [ undef, %entry ], [ %select, %loop ]
+  %gep = getelementptr inbounds i32, ptr %src, i32 %iv
+  %l = load i32, ptr %gep
+  %c = icmp eq i32 %l, 1
+  %select = select i1 %c, i64 %red, i64 %a
+  %add = add nuw i32 %iv, 1
+  %ec = icmp eq i32 %iv, 32
+  br i1 %ec, label %exit, label %loop
+
+exit:
+  %phi = phi i64 [ %select, %loop ]
+  ret i64 %phi
+}
+
+define i64 @pr62565_incoming_value_known_poison(i64 %a, ptr %src) {
+; CHECK-LABEL: define i64 @pr62565_incoming_value_known_poison
+; CHECK-SAME: (i64 [[A:%.*]], ptr [[SRC:%.*]]) {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br i1 false, label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
+; CHECK:       vector.ph:
+; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <2 x i64> poison, i64 [[A]], i64 0
+; CHECK-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <2 x i64> [[BROADCAST_SPLATINSERT]], <2 x i64> poison, <2 x i32> zeroinitializer
+; CHECK-NEXT:    br label [[VECTOR_BODY:%.*]]
+; CHECK:       vector.body:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i32 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[VEC_PHI:%.*]] = phi <2 x i64> [ poison, [[VECTOR_PH]] ], [ [[TMP4:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[OFFSET_IDX:%.*]] = add i32 1, [[INDEX]]
+; CHECK-NEXT:    [[TMP0:%.*]] = add i32 [[OFFSET_IDX]], 0
+; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i32, ptr [[SRC]], i32 [[TMP0]]
+; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i32, ptr [[TMP1]], i32 0
+; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <2 x i32>, ptr [[TMP2]], align 4
+; CHECK-NEXT:    [[TMP3:%.*]] = icmp eq <2 x i32> [[WIDE_LOAD]], <i32 1, i32 1>
+; CHECK-NEXT:    [[TMP4]] = select <2 x i1> [[TMP3]], <2 x i64> [[VEC_PHI]], <2 x i64> [[BROADCAST_SPLAT]]
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i32 [[INDEX]], 2
+; CHECK-NEXT:    [[TMP5:%.*]] = icmp eq i32 [[INDEX_NEXT]], 32
+; CHECK-NEXT:    br i1 [[TMP5]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
+; CHECK:       middle.block:
+; CHECK-NEXT:    [[RDX_SELECT_CMP:%.*]] = icmp ne <2 x i64> [[TMP4]], poison
+; CHECK-NEXT:    [[TMP6:%.*]] = call i1 @llvm.vector.reduce.or.v2i1(<2 x i1> [[RDX_SELECT_CMP]])
+; CHECK-NEXT:    [[RDX_SELECT:%.*]] = select i1 [[TMP6]], i64 [[A]], i64 poison
+; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i32 32, 32
+; CHECK-NEXT:    br i1 [[CMP_N]], label [[EXIT:%.*]], label [[SCALAR_PH]]
+; CHECK:       scalar.ph:
+; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i32 [ 33, [[MIDDLE_BLOCK]] ], [ 1, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i64 [ poison, [[ENTRY]] ], [ [[RDX_SELECT]], [[MIDDLE_BLOCK]] ]
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i32 [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ], [ [[ADD:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[RED:%.*]] = phi i64 [ [[BC_MERGE_RDX]], [[SCALAR_PH]] ], [ [[SELECT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[GEP:%.*]] = getelementptr inbounds i32, ptr [[SRC]], i32 [[IV]]
+; CHECK-NEXT:    [[L:%.*]] = load i32, ptr [[GEP]], align 4
+; CHECK-NEXT:    [[C:%.*]] = icmp eq i32 [[L]], 1
+; CHECK-NEXT:    [[SELECT]] = select i1 [[C]], i64 [[RED]], i64 [[A]]
+; CHECK-NEXT:    [[ADD]] = add nuw i32 [[IV]], 1
+; CHECK-NEXT:    [[EC:%.*]] = icmp eq i32 [[IV]], 32
+; CHECK-NEXT:    br i1 [[EC]], label [[EXIT]], label [[LOOP]], !llvm.loop [[LOOP5:![0-9]+]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[PHI:%.*]] = phi i64 [ [[SELECT]], [[LOOP]] ], [ [[RDX_SELECT]], [[MIDDLE_BLOCK]] ]
+; CHECK-NEXT:    ret i64 [[PHI]]
+;
+entry:
+  br label %loop
+
+loop:
+  %iv = phi i32 [ 1, %entry ], [ %add, %loop ]
+  %red = phi i64 [ poison, %entry ], [ %select, %loop ]
+  %gep = getelementptr inbounds i32, ptr %src, i32 %iv
+  %l = load i32, ptr %gep
+  %c = icmp eq i32 %l, 1
+  %select = select i1 %c, i64 %red, i64 %a
+  %add = add nuw i32 %iv, 1
+  %ec = icmp eq i32 %iv, 32
+  br i1 %ec, label %exit, label %loop
+
+exit:
+  %phi = phi i64 [ %select, %loop ]
+  ret i64 %phi
+}
+
+define i64 @pr62565_incoming_value_may_be_poison(i64 %a, ptr %src, i64 %start) {
+; CHECK-LABEL: define i64 @pr62565_incoming_value_may_be_poison
+; CHECK-SAME: (i64 [[A:%.*]], ptr [[SRC:%.*]], i64 [[START:%.*]]) {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br i1 false, label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
+; CHECK:       vector.ph:
+; CHECK-NEXT:    [[MINMAX_IDENT_SPLATINSERT:%.*]] = insertelement <2 x i64> poison, i64 [[START]], i64 0
+; CHECK-NEXT:    [[MINMAX_IDENT_SPLAT:%.*]] = shufflevector <2 x i64> [[MINMAX_IDENT_SPLATINSERT]], <2 x i64> poison, <2 x i32> zeroinitializer
+; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <2 x i64> poison, i64 [[A]], i64 0
+; CHECK-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <2 x i64> [[BROADCAST_SPLATINSERT]], <2 x i64> poison, <2 x i32> zeroinitializer
+; CHECK-NEXT:    br label [[VECTOR_BODY:%.*]]
+; CHECK:       vector.body:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i32 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[VEC_PHI:%.*]] = phi <2 x i64> [ [[MINMAX_IDENT_SPLAT]], [[VECTOR_PH]] ], [ [[TMP4:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[OFFSET_IDX:%.*]] = add i32 1, [[INDEX]]
+; CHECK-NEXT:    [[TMP0:%.*]] = add i32 [[OFFSET_IDX]], 0
+; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i32, ptr [[SRC]], i32 [[TMP0]]
+; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i32, ptr [[TMP1]], i32 0
+; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <2 x i32>, ptr [[TMP2]], align 4
+; CHECK-NEXT:    [[TMP3:%.*]] = icmp eq <2 x i32> [[WIDE_LOAD]], <i32 1, i32 1>
+; CHECK-NEXT:    [[TMP4]] = select <2 x i1> [[TMP3]], <2 x i64> [[VEC_PHI]], <2 x i64> [[BROADCAST_SPLAT]]
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i32 [[INDEX]], 2
+; CHECK-NEXT:    [[TMP5:%.*]] = icmp eq i32 [[INDEX_NEXT]], 32
+; CHECK-NEXT:    br i1 [[TMP5]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
+; CHECK:       middle.block:
+; CHECK-NEXT:    [[DOTSPLATINSERT:%.*]] = insertelement <2 x i64> poison, i64 [[START]], i64 0
+; CHECK-NEXT:    [[DOTSPLAT:%.*]] = shufflevector <2 x i64> [[DOTSPLATINSERT]], <2 x i64> poison, <2 x i32> zeroinitializer
+; CHECK-NEXT:    [[RDX_SELECT_CMP:%.*]] = icmp ne <2 x i64> [[TMP4]], [[DOTSPLAT]]
+; CHECK-NEXT:    [[TMP6:%.*]] = call i1 @llvm.vector.reduce.or.v2i1(<2 x i1> [[RDX_SELECT_CMP]])
+; CHECK-NEXT:    [[RDX_SELECT:%.*]] = select i1 [[TMP6]], i64 [[A]], i64 [[START]]
+; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i32 32, 32
+; CHECK-NEXT:    br i1 [[CMP_N]], label [[EXIT:%.*]], label [[SCALAR_PH]]
+; CHECK:       scalar.ph:
+; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i32 [ 33, [[MIDDLE_BLOCK]] ], [ 1, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i64 [ [[START]], [[ENTRY]] ], [ [[RDX_SELECT]], [[MIDDLE_BLOCK]] ]
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i32 [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ], [ [[ADD:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[RED:%.*]] = phi i64 [ [[BC_MERGE_RDX]], [[SCALAR_PH]] ], [ [[SELECT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[GEP:%.*]] = getelementptr inbounds i32, ptr [[SRC]], i32 [[IV]]
+; CHECK-NEXT:    [[L:%.*]] = load i32, ptr [[GEP]], align 4
+; CHECK-NEXT:    [[C:%.*]] = icmp eq i32 [[L]], 1
+; CHECK-NEXT:    [[SELECT]] = select i1 [[C]], i64 [[RED]], i64 [[A]]
+; CHECK-NEXT:    [[ADD]] = add nuw i32 [[IV]], 1
+; CHECK-NEXT:    [[EC:%.*]] = icmp eq i32 [[IV]], 32
+; CHECK-NEXT:    br i1 [[EC]], label [[EXIT]], label [[LOOP]], !llvm.loop [[LOOP7:![0-9]+]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[PHI:%.*]] = phi i64 [ [[SELECT]], [[LOOP]] ], [ [[RDX_SELECT]], [[MIDDLE_BLOCK]] ]
+; CHECK-NEXT:    ret i64 [[PHI]]
+;
+entry:
+  br label %loop
+
+loop:
+  %iv = phi i32 [ 1, %entry ], [ %add, %loop ]
+  %red = phi i64 [ %start, %entry ], [ %select, %loop ]
+  %gep = getelementptr inbounds i32, ptr %src, i32 %iv
+  %l = load i32, ptr %gep
+  %c = icmp eq i32 %l, 1
+  %select = select i1 %c, i64 %red, i64 %a
+  %add = add nuw i32 %iv, 1
+  %ec = icmp eq i32 %iv, 32
+  br i1 %ec, label %exit, label %loop
+
+exit:
+  %phi = phi i64 [ %select, %loop ]
+  ret i64 %phi
+}