From 879463206e16eb0a03dd86c14aeba792355dea47 Mon Sep 17 00:00:00 2001 From: Ahmed Bougacha Date: Mon, 1 Dec 2014 20:52:32 +0000 Subject: [PATCH] [AArch64] Fix v2i8->i16 bitcast legalization. r213378 improved f16 bitcasts, so that they go directly through subregs, instead of through the stack. That code now causes an assertion failure for bitcasts from other 16-bits types (most importantly v2i8). Correct that by doing the custom lowering for i16 bitcasts only when the input is an f16. Part of PR21549. Differential Revision: http://reviews.llvm.org/D6307 llvm-svn: 223074 --- llvm/lib/Target/AArch64/AArch64ISelLowering.cpp | 9 ++++----- llvm/test/CodeGen/AArch64/bitcast-v2i8.ll | 15 +++++++++++++++ 2 files changed, 19 insertions(+), 5 deletions(-) create mode 100644 llvm/test/CodeGen/AArch64/bitcast-v2i8.ll diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp index 6da468e..16ad2f6 100644 --- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp +++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp @@ -8697,13 +8697,12 @@ bool AArch64TargetLowering::getPostIndexedAddressParts( static void ReplaceBITCASTResults(SDNode *N, SmallVectorImpl &Results, SelectionDAG &DAG) { - if (N->getValueType(0) != MVT::i16) - return; - SDLoc DL(N); SDValue Op = N->getOperand(0); - assert(Op.getValueType() == MVT::f16 && - "Inconsistent bitcast? Only 16-bit types should be i16 or f16"); + + if (N->getValueType(0) != MVT::i16 || Op.getValueType() != MVT::f16) + return; + Op = SDValue( DAG.getMachineNode(TargetOpcode::INSERT_SUBREG, DL, MVT::f32, DAG.getUNDEF(MVT::i32), Op, diff --git a/llvm/test/CodeGen/AArch64/bitcast-v2i8.ll b/llvm/test/CodeGen/AArch64/bitcast-v2i8.ll new file mode 100644 index 0000000..4bdac64 --- /dev/null +++ b/llvm/test/CodeGen/AArch64/bitcast-v2i8.ll @@ -0,0 +1,15 @@ +; RUN: llc < %s -mtriple=aarch64-apple-ios | FileCheck %s + +; Part of PR21549: going through the stack isn't ideal but is correct. + +define i16 @test_bitcast_v2i8_to_i16(<2 x i8> %a) { +; CHECK-LABEL: test_bitcast_v2i8_to_i16 +; CHECK: mov.s [[WREG_HI:w[0-9]+]], v0[1] +; CHECK-NEXT: fmov [[WREG_LO:w[0-9]+]], s0 +; CHECK-NEXT: strb [[WREG_HI]], [sp, #15] +; CHECK-NEXT: strb [[WREG_LO]], [sp, #14] +; CHECK-NEXT: ldrh w0, [sp, #14] + + %aa = bitcast <2 x i8> %a to i16 + ret i16 %aa +} -- 2.7.4