From 94db67f0e1c3e082fd89a84fa79c6d84631227ba Mon Sep 17 00:00:00 2001
From: Roman Lebedev <lebedev.ri@gmail.com>
Date: Sun, 8 Sep 2019 19:36:13 +0000
Subject: [PATCH] [X86] X86DAGToDAGISel::combineIncDecVector(): call
 getSplatBuildVector() manually

As reported in post-commit review of r370327,
there is some case where the code crashes.

As discussed with Craig Topper, the problem is that getConstant()
internally calls getSplatBuildVector(), so we don't insert
the constant itself.

If we do that manually we're good.

llvm-svn: 371346
---
 llvm/lib/Target/X86/X86ISelDAGToDAG.cpp            |  9 ++--
 llvm/test/CodeGen/X86/combineIncDecVector-crash.ll | 51 ++++++++++++++++++++++
 2 files changed, 57 insertions(+), 3 deletions(-)
 create mode 100644 llvm/test/CodeGen/X86/combineIncDecVector-crash.ll

diff --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
index a8cd007..64309bc 100644
--- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -3797,15 +3797,18 @@ bool X86DAGToDAGISel::combineIncDecVector(SDNode *Node) {
     return false;
 
   SDLoc DL(Node);
-  SDValue AllOnesVec;
+  SDValue OneConstant, AllOnesVec;
 
   APInt Ones = APInt::getAllOnesValue(32);
   assert(VT.getSizeInBits() % 32 == 0 &&
          "Expected bit count to be a multiple of 32");
+  OneConstant = CurDAG->getConstant(Ones, DL, MVT::i32);
+  insertDAGNode(*CurDAG, X, OneConstant);
+
   unsigned NumElts = VT.getSizeInBits() / 32;
   assert(NumElts > 0 && "Expected to get non-empty vector.");
-  AllOnesVec =
-      CurDAG->getConstant(Ones, DL, MVT::getVectorVT(MVT::i32, NumElts));
+  AllOnesVec = CurDAG->getSplatBuildVector(MVT::getVectorVT(MVT::i32, NumElts),
+                                           DL, OneConstant);
   insertDAGNode(*CurDAG, X, AllOnesVec);
 
   AllOnesVec = CurDAG->getBitcast(VT, AllOnesVec);
diff --git a/llvm/test/CodeGen/X86/combineIncDecVector-crash.ll b/llvm/test/CodeGen/X86/combineIncDecVector-crash.ll
new file mode 100644
index 0000000..8dea7a5
--- /dev/null
+++ b/llvm/test/CodeGen/X86/combineIncDecVector-crash.ll
@@ -0,0 +1,51 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s | FileCheck %s
+
+; This used to crash, just ensure that it doesn't.
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128-ni:1"
+target triple = "x86_64-unknown-linux-gnu"
+
+define void @TestvMeth(i32 %0, i64 %1) gc "statepoint-example" !prof !1 {
+; CHECK-LABEL: TestvMeth:
+; CHECK:       # %bb.0: # %bci_0
+; CHECK-NEXT:    subq $24, %rsp
+; CHECK-NEXT:    .cfi_def_cfa_offset 32
+; CHECK-NEXT:    movq %rsi, {{[0-9]+}}(%rsp)
+; CHECK-NEXT:    movl %edi, {{[0-9]+}}(%rsp)
+; CHECK-NEXT:    movl $10, %esi
+; CHECK-NEXT:    movl $10, %edx
+; CHECK-NEXT:    movl $400, %ecx # imm = 0x190
+; CHECK-NEXT:    callq newarray
+; CHECK-NEXT:  .Ltmp0:
+; CHECK-NEXT:    movss {{.*#+}} xmm0 = mem[0],zero,zero,zero
+; CHECK-NEXT:    addss (%rax), %xmm0
+; CHECK-NEXT:    movdqu (%rax), %xmm1
+; CHECK-NEXT:    pcmpeqd %xmm2, %xmm2
+; CHECK-NEXT:    psubd %xmm2, %xmm1
+; CHECK-NEXT:    movdqu %xmm1, (%rax)
+; CHECK-NEXT:    movss %xmm0, (%rax)
+bci_0:
+   %token418 = call token (i64, i32, i8 * (i64, i32, i32, i32)*, i32,
+i32, ...) @llvm.experimental.gc.statepoint.p0f_p1i8i64i32i32i32f(i64
+2882400000, i32 0, i8 * (i64, i32, i32, i32)* nonnull @newarray, i32 4,
+i32 0, i64 undef, i32 10, i32 10, i32 400, i32 0, i32 35, i32 0, i32 1,
+i32 0, i32 43, i32 1, i32 13, i32 0, i32 3, i32 400, i32 3, i32 %0, i32
+4, i64 %1, i32 7, i8* null, i32 3, i32 -11464, i32 7, i8* null, i32 3,
+i32 -243, i32 3, i32 14, i32 3, i32 117, i32 3, i32 -13, i32 3, i32 -15,
+i32 3, i32 -210, i32 3, i32 541, i32 7, i8* null)
+   %v2 = load atomic float, float * undef unordered, align 4
+   %v3 = load <4 x i32>, <4 x i32> * undef, align 4
+   %v4 = add <4 x i32> %v3, <i32 1, i32 1, i32 1, i32 1>
+   store <4 x i32> %v4, <4 x i32> * undef, align 4
+   %v5 = fadd float %v2, 1.500000e+01
+   store atomic float %v5, float * undef unordered, align 4
+   unreachable
+}
+
+declare i32* @personality_function()
+declare i8 * @newarray(i64, i32, i32, i32)
+declare token @llvm.experimental.gc.statepoint.p0f_p1i8i64i32i32i32f(i64
+immarg, i32 immarg, i8 * (i64, i32, i32, i32)*, i32 immarg, i32 immarg, ...)
+
+!1 = !{!"function_entry_count", i64 32768}
-- 
2.7.4