commit 11a332d08d9c1ccfd17a14cb47e209444fd48df5
author Thomas Lively <tlively@google.com> Fri Oct 19 19:08:06 2018 +0000
committer Thomas Lively <tlively@google.com> Fri Oct 19 19:08:06 2018 +0000
tree 04e15be2220de0c1f20be2cbb70fbb48867c991e
parent 2bfe759a8d7f4e544ac0f079d447f33c0b4dcf9c

[WebAssembly] Handle undefined lane indices in SIMD patterns

Summary:
Undefined indices in shuffles can be used when not all lanes of the
output vector will be used. This happens for example in the expansion
of vector reduce operations. Regardless, undefs are legal as lane
indices in IR and should be supported.

Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D53057

llvm-svn: 344803

llvm/lib/Target/WebAssembly/WebAssemblyInstrSIMD.td

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyInstrSIMD.td b/llvm/lib/Target/WebAssembly/WebAssemblyInstrSIMD.td
index b0fd6ca..95c8726 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyInstrSIMD.td
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyInstrSIMD.td
@@ -181,6 +181,28 @@
 def : Pat<(i32 (vector_extract (v8i16 V128:$vec), (i32 LaneIdx8:$idx))),
           (EXTRACT_LANE_v8i16_u V128:$vec, (i32 LaneIdx8:$idx))>;
 
+// Lower undef lane indices to zero
+def : Pat<(and (i32 (vector_extract (v16i8 V128:$vec), undef)), (i32 0xff)),
+          (EXTRACT_LANE_v16i8_u V128:$vec, 0)>;
+def : Pat<(and (i32 (vector_extract (v8i16 V128:$vec), undef)), (i32 0xffff)),
+          (EXTRACT_LANE_v8i16_u V128:$vec, 0)>;
+def : Pat<(i32 (vector_extract (v16i8 V128:$vec), undef)),
+          (EXTRACT_LANE_v16i8_u V128:$vec, 0)>;
+def : Pat<(i32 (vector_extract (v8i16 V128:$vec), undef)),
+          (EXTRACT_LANE_v8i16_u V128:$vec, 0)>;
+def : Pat<(sext_inreg (i32 (vector_extract (v16i8 V128:$vec), undef)), i8),
+          (EXTRACT_LANE_v16i8_s V128:$vec, 0)>;
+def : Pat<(sext_inreg (i32 (vector_extract (v8i16 V128:$vec), undef)), i16),
+          (EXTRACT_LANE_v8i16_s V128:$vec, 0)>;
+def : Pat<(vector_extract (v4i32 V128:$vec), undef),
+          (EXTRACT_LANE_v4i32 V128:$vec, 0)>;
+def : Pat<(vector_extract (v2i64 V128:$vec), undef),
+          (EXTRACT_LANE_v2i64 V128:$vec, 0)>;
+def : Pat<(vector_extract (v4f32 V128:$vec), undef),
+          (EXTRACT_LANE_v4f32 V128:$vec, 0)>;
+def : Pat<(vector_extract (v2f64 V128:$vec), undef),
+          (EXTRACT_LANE_v2f64 V128:$vec, 0)>;
+
 // Replace lane value: replace_lane
 multiclass ReplaceLane<ValueType vec_t, string vec, ImmLeaf imm_t,
                        WebAssemblyRegClass reg_t, ValueType lane_t,
@@ -201,6 +223,20 @@
 defm "" : ReplaceLane<v4f32, "f32x4", LaneIdx4, F32, f32, 21>;
 defm "" : ReplaceLane<v2f64, "f64x2", LaneIdx2, F64, f64, 22>;
 
+// Lower undef lane indices to zero
+def : Pat<(vector_insert (v16i8 V128:$vec), I32:$x, undef),
+          (REPLACE_LANE_v16i8 V128:$vec, 0, I32:$x)>;
+def : Pat<(vector_insert (v8i16 V128:$vec), I32:$x, undef),
+          (REPLACE_LANE_v8i16 V128:$vec, 0, I32:$x)>;
+def : Pat<(vector_insert (v4i32 V128:$vec), I32:$x, undef),
+          (REPLACE_LANE_v4i32 V128:$vec, 0, I32:$x)>;
+def : Pat<(vector_insert (v2i64 V128:$vec), I64:$x, undef),
+          (REPLACE_LANE_v2i64 V128:$vec, 0, I64:$x)>;
+def : Pat<(vector_insert (v4f32 V128:$vec), F32:$x, undef),
+          (REPLACE_LANE_v4f32 V128:$vec, 0, F32:$x)>;
+def : Pat<(vector_insert (v2f64 V128:$vec), F64:$x, undef),
+          (REPLACE_LANE_v2f64 V128:$vec, 0, F64:$x)>;
+
 // Arbitrary other BUILD_VECTOR patterns
 def : Pat<(v16i8 (build_vector
             (i32 I32:$x0), (i32 I32:$x1), (i32 I32:$x2), (i32 I32:$x3),