sys-devel/llvm: Backport X86 codegen bugfix for Chromium builds

Backport the X86 codegen fix to 7.0.0 and 6.0.1, to ~arch.  Hopefully
people will get this along with libffi-enforced rebuild.  We can
stabilize 6.0.1-r2 either when stable users start hitting this, or when
libffi gets stable.

Bug: https://bugs.gentoo.org/664868
Signed-off-by: Michał Górny <mgorny@gentoo.org>

1 files changed, 110 insertions, 0 deletions

diff --git a/sys-devel/llvm/files/7.0.0/0001-X86-Stop-X86DomainReassignment-from-creating-copies-.patch b/sys-devel/llvm/files/7.0.0/0001-X86-Stop-X86DomainReassignment-from-creating-copies-.patch
new file mode 100644
index 000000000000..f38907cdd4c1
--- /dev/null
+++ b/sys-devel/llvm/files/7.0.0/0001-X86-Stop-X86DomainReassignment-from-creating-copies-.patch
@@ -0,0 +1,110 @@
+From 72da952b396f43d2ce6ca20a0f0d75212fea6b28 Mon Sep 17 00:00:00 2001
+From: Craig Topper <craig.topper@intel.com>
+Date: Mon, 1 Oct 2018 07:08:41 +0000
+Subject: [PATCH] [X86] Stop X86DomainReassignment from creating copies between
+ GR8/GR16 physical registers and k-registers.
+
+We can only copy between a k-register and a GR32/GR64 register.
+
+This patch detects that the copy will be illegal and prevents the domain reassignment from happening for that closure.
+
+This probably isn't the best fix, and we should probably figure out how to handle this correctly.
+
+Fixes PR38803.
+
+git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@343443 91177308-0d34-0410-b5e6-96231b3b80d8
+---
+ lib/Target/X86/X86DomainReassignment.cpp | 21 +++++++++++
+ test/CodeGen/X86/pr38803.ll              | 48 ++++++++++++++++++++++++
+ 2 files changed, 69 insertions(+)
+ create mode 100644 test/CodeGen/X86/pr38803.ll
+
+diff --git a/lib/Target/X86/X86DomainReassignment.cpp b/lib/Target/X86/X86DomainReassignment.cpp
+index 5196446b39e..62588e9509d 100644
+--- a/lib/Target/X86/X86DomainReassignment.cpp
++++ b/lib/Target/X86/X86DomainReassignment.cpp
+@@ -217,6 +217,27 @@ public:
+   InstrCOPYReplacer(unsigned SrcOpcode, RegDomain DstDomain, unsigned DstOpcode)
+       : InstrReplacer(SrcOpcode, DstOpcode), DstDomain(DstDomain) {}
+ 
++  bool isLegal(const MachineInstr *MI,
++               const TargetInstrInfo *TII) const override {
++    if (!InstrConverterBase::isLegal(MI, TII))
++      return false;
++
++    // Don't allow copies to/flow GR8/GR16 physical registers.
++    // FIXME: Is there some better way to support this?
++    unsigned DstReg = MI->getOperand(0).getReg();
++    if (TargetRegisterInfo::isPhysicalRegister(DstReg) &&
++        (X86::GR8RegClass.contains(DstReg) ||
++         X86::GR16RegClass.contains(DstReg)))
++      return false;
++    unsigned SrcReg = MI->getOperand(1).getReg();
++    if (TargetRegisterInfo::isPhysicalRegister(SrcReg) &&
++        (X86::GR8RegClass.contains(SrcReg) ||
++         X86::GR16RegClass.contains(SrcReg)))
++      return false;
++
++    return true;
++  }
++
+   double getExtraCost(const MachineInstr *MI,
+                       MachineRegisterInfo *MRI) const override {
+     assert(MI->getOpcode() == TargetOpcode::COPY && "Expected a COPY");
+diff --git a/test/CodeGen/X86/pr38803.ll b/test/CodeGen/X86/pr38803.ll
+new file mode 100644
+index 00000000000..a1ca27d89b0
+--- /dev/null
++++ b/test/CodeGen/X86/pr38803.ll
+@@ -0,0 +1,48 @@
++; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
++; RUN: llc < %s -mcpu=skylake-avx512 -mtriple=x86_64-unknown-unknown | FileCheck %s
++
++@b = local_unnamed_addr global i32 0, align 4
++@c = local_unnamed_addr global i32 0, align 4
++@d = local_unnamed_addr global float 0.000000e+00, align 4
++
++define float @_Z3fn2v() {
++; CHECK-LABEL: _Z3fn2v:
++; CHECK:       # %bb.0: # %entry
++; CHECK-NEXT:    pushq %rax
++; CHECK-NEXT:    .cfi_def_cfa_offset 16
++; CHECK-NEXT:    callq _Z1av
++; CHECK-NEXT:    # kill: def $al killed $al def $eax
++; CHECK-NEXT:    kmovd %eax, %k1
++; CHECK-NEXT:    vmovss {{.*#+}} xmm0 = mem[0],zero,zero,zero
++; CHECK-NEXT:    vmovss %xmm0, %xmm0, %xmm0 {%k1} {z}
++; CHECK-NEXT:    cmpl $0, {{.*}}(%rip)
++; CHECK-NEXT:    je .LBB0_2
++; CHECK-NEXT:  # %bb.1: # %if.then
++; CHECK-NEXT:    vcvtsi2ssl {{.*}}(%rip), %xmm1, %xmm1
++; CHECK-NEXT:    kmovd %eax, %k1
++; CHECK-NEXT:    vxorps %xmm2, %xmm2, %xmm2
++; CHECK-NEXT:    vmovss %xmm2, %xmm0, %xmm1 {%k1}
++; CHECK-NEXT:    vmovss %xmm1, {{.*}}(%rip)
++; CHECK-NEXT:  .LBB0_2: # %if.end
++; CHECK-NEXT:    popq %rax
++; CHECK-NEXT:    .cfi_def_cfa_offset 8
++; CHECK-NEXT:    retq
++entry:
++  %call = tail call zeroext i1 @_Z1av()
++  %cond = select i1 %call, float 7.500000e-01, float 0.000000e+00
++  %0 = load i32, i32* @c, align 4
++  %tobool2 = icmp eq i32 %0, 0
++  br i1 %tobool2, label %if.end, label %if.then
++
++if.then:                                          ; preds = %entry
++  %1 = load i32, i32* @b, align 4
++  %2 = sitofp i32 %1 to float
++  %conv5 = select i1 %call, float 0.000000e+00, float %2
++  store float %conv5, float* @d, align 4
++  br label %if.end
++
++if.end:                                           ; preds = %entry, %if.then
++  ret float %cond
++}
++
++declare zeroext i1 @_Z1av()
+-- 
+2.19.0
+