[WebAssembly] Fix ISel crash on sext_inreg/extract type mismatch

Summary:
Adjusts the index and adds a bitcast around the vector operand of
EXTRACT_VECTOR_ELT so that its lane type matches the source type of
its parent sext_inreg. Without this bitcast the ISel patterns do not
match and ISel fails.

Reviewers: aheejin

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62646

llvm-svn: 362547

1 files changed, 59 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/WebAssembly/simd-extended-extract.ll b/llvm/test/CodeGen/WebAssembly/simd-extended-extract.ll
new file mode 100644
index 00000000000..b6e35f5f93a
--- /dev/null
+++ b/llvm/test/CodeGen/WebAssembly/simd-extended-extract.ll
@@ -0,0 +1,59 @@
+; RUN: llc < %s -asm-verbose=false -verify-machineinstrs -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -mattr=+simd128 | FileCheck %s
+
+; Regression test for an issue with patterns like the following:
+;
+;     t101: v4i32 = BUILD_VECTOR t99, t99, t99, t99
+;         t92: i32 = extract_vector_elt t101, Constant:i32<0>
+;             t89: i32 = sign_extend_inreg t92, ValueType:ch:i8
+;
+; Notice that the sign_extend_inreg has source value type i8 but the
+; extracted vector has type v4i32. There are no ISel patterns that
+; handle mismatched types like this, so we insert a bitcast before the
+; extract. This was previously an ISel failure. This test case is
+; reduced from a private user bug report, and the vector extracts are
+; optimized out via subsequent DAG combines.
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-unknown"
+
+; CHECK-LABEL: foo:
+
+; CHECK: i32.load8_u
+; CHECK: i32x4.splat
+; CHECK: i32.load8_u
+; CHECK: i32x4.replace_lane   1
+; CHECK: i32.load8_u
+; CHECK: i32x4.replace_lane   2
+; CHECK: i32.load8_u
+; CHECK: i32x4.replace_lane   3
+
+; CHECK: i8x16.extract_lane_s 0
+; CHECK: f64.convert_i32_s
+; CHECK: f32.demote_f64
+; CHECK: f32x4.splat
+
+; CHECK: i8x16.extract_lane_s 4
+; CHECK: f64.convert_i32_s
+; CHECK: f32.demote_f64
+; CHECK: f32x4.replace_lane   1
+
+; CHECK: i8x16.extract_lane_s 8
+; CHECK: f64.convert_i32_s
+; CHECK: f32.demote_f64
+; CHECK: f32x4.replace_lane   2
+
+; CHECK: i8x16.extract_lane_s 12
+; CHECK: f64.convert_i32_s
+; CHECK: f32.demote_f64
+; CHECK: f32x4.replace_lane   3
+
+; CHECK: v128.store
+define void @foo(<4 x i8>* %p) {
+  %1 = load <4 x i8>, <4 x i8>* %p
+  %2 = sitofp <4 x i8> %1 to <4 x double>
+  %3 = fmul <4 x double> zeroinitializer, %2
+  %4 = fadd <4 x double> %3, zeroinitializer
+  %5 = fptrunc <4 x double> %4 to <4 x float>
+  store <4 x float> %5, <4 x float>* undef
+  ret void
+}