[llvm] r371346 - [X86] X86DAGToDAGISel::combineIncDecVector(): call getSplatBuildVector() manually

[Roman Lebedev via llvm-commits]

Author: lebedevri
Date: Sun Sep  8 12:36:13 2019
New Revision: 371346

URL: http://llvm.org/viewvc/llvm-project?rev=371346&view=rev
Log:
[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.

Added:
    llvm/trunk/test/CodeGen/X86/combineIncDecVector-crash.ll
Modified:
    llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp

Modified: llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp?rev=371346&r1=371345&r2=371346&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp Sun Sep  8 12:36:13 2019
@@ -3797,15 +3797,18 @@ bool X86DAGToDAGISel::combineIncDecVecto
     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);

Added: llvm/trunk/test/CodeGen/X86/combineIncDecVector-crash.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/combineIncDecVector-crash.ll?rev=371346&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/combineIncDecVector-crash.ll (added)
+++ llvm/trunk/test/CodeGen/X86/combineIncDecVector-crash.ll Sun Sep  8 12:36:13 2019
@@ -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}