[PATCH] D107795: [DAGCombine] Check the legality of the index of EXTRACT_SUBVECTOR

[guopeilin via Phabricator via llvm-commits]

guopeilin updated this revision to Diff 368287.
guopeilin retitled this revision from " [AArch64][DAGCombine] Check the legality of the index of EXTRACT_SUBVECTOR" to "[DAGCombine] Check the legality of the index of EXTRACT_SUBVECTOR".
guopeilin added a comment.
Herald added subscribers: kerbowa, nhaehnle, jvesely.

Hi all!
Updata a new test case.
Function test2 will fail due to assertion of invalid offset of EXTRACT_SUBVECTOR.
Also modify the AMD test case


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D107795/new/

https://reviews.llvm.org/D107795

Files:
  llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
  llvm/test/CodeGen/AArch64/aarch64-avoid-illegal-extract-subvector.ll
  llvm/test/CodeGen/AMDGPU/llvm.amdgcn.struct.buffer.load.format.v3f16.ll


Index: llvm/test/CodeGen/AMDGPU/llvm.amdgcn.struct.buffer.load.format.v3f16.ll
===================================================================
--- llvm/test/CodeGen/AMDGPU/llvm.amdgcn.struct.buffer.load.format.v3f16.ll
+++ llvm/test/CodeGen/AMDGPU/llvm.amdgcn.struct.buffer.load.format.v3f16.ll
@@ -79,9 +79,8 @@
 ; GFX8-NEXT:  ; %bb.2:
 ; GFX8-NEXT:    s_mov_b64 exec, s[2:3]
 ; GFX8-NEXT:    s_waitcnt vmcnt(0)
-; GFX8-NEXT:    v_alignbit_b32 v0, v6, v5, 16
-; GFX8-NEXT:    v_lshrrev_b32_e32 v1, 16, v0
-; GFX8-NEXT:    v_and_b32_e32 v0, 0xffff, v0
+; GFX8-NEXT:    v_lshrrev_b32_e32 v0, 16, v5
+; GFX8-NEXT:    v_and_b32_e32 v1, 0xffff, v6
 ; GFX8-NEXT:    v_mov_b32_e32 v2, 0
 ; GFX8-NEXT:    s_mov_b32 m0, -1
 ; GFX8-NEXT:    ds_write2_b32 v2, v0, v1 offset0:7 offset1:8
Index: llvm/test/CodeGen/AArch64/aarch64-avoid-illegal-extract-subvector.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/AArch64/aarch64-avoid-illegal-extract-subvector.ll
@@ -0,0 +1,40 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=aarch64-none-linux-gnu < %s -o -| FileCheck %s
+define <2 x i64> @test1(<4 x i32> %x) #0 {
+; CHECK-LABEL: test1:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    mov w8, v0.s[1]
+; CHECK-NEXT:    mov w9, v0.s[2]
+; CHECK-NEXT:    fmov d0, x8
+; CHECK-NEXT:    mov v0.d[1], x9
+; CHECK-NEXT:    ret
+  %i1 = extractelement <4 x i32> %x, i32 1
+  %zi1 = zext i32 %i1 to i64
+  %i2 = extractelement <4 x i32> %x, i32 2
+  %zi2 = zext i32 %i2 to i64
+  %v1 = insertelement <2 x i64> undef, i64 %zi1, i32 0
+  %v2 = insertelement <2 x i64> %v1, i64 %zi2, i32 1
+  ret <2 x i64> %v2
+}
+
+define <4 x i64> @test2(<4 x i32> %0) {
+; CHECK-LABEL: test2:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    adrp x8, .LCPI1_0
+; CHECK-NEXT:    ldr q1, [x8, :lo12:.LCPI1_0]
+; CHECK-NEXT:    add v0.4s, v0.4s, v1.4s
+; CHECK-NEXT:    mov w8, v0.s[1]
+; CHECK-NEXT:    mov w9, v0.s[2]
+; CHECK-NEXT:    fmov d1, x8
+; CHECK-NEXT:    mov v1.d[1], x9
+; CHECK-NEXT:    ret
+entry:
+  %1 = add <4 x i32> %0, <i32 -4, i32 -8, i32 -12, i32 -16>
+  %2 = extractelement <4 x i32> %1, i32 1
+  %zext1 = zext i32 %2 to i64
+  %3 = extractelement <4 x i32> %1, i32 2
+  %zext2 = zext i32 %3 to i64
+  %4 = insertelement <4 x i64> undef, i64 %zext1, i32 2
+  %5 = insertelement <4 x i64> %4, i64 %zext2, i32 3
+  ret <4 x i64> %5
+}
Index: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -19695,8 +19695,10 @@
 
   // Make sure the first element matches
   // (zext (extract_vector_elt X, C))
+  // Offset must be a constant multiple of the
+  // known-minimum vector length of the result type.
   int64_t Offset = checkElem(Op0);
-  if (Offset < 0)
+  if (Offset < 0 || (Offset % VT.getVectorNumElements()) != 0)
     return SDValue();
 
   unsigned NumElems = N->getNumOperands();


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