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[FastISel][X86] Add large code model support for materializing floating-point constants. 

In the large code model for X86 floating-point constants are placed in the
constant pool and materialized by loading from it. Since the constant pool
could be far away, a PC relative load might not work. Therefore we first
materialize the address of the constant pool with a movabsq and then load
from there the floating-point value.

Fixes <rdar://problem/17674628>.

llvm-svn: 215595
This commit is contained in:
Juergen Ributzka 2014-08-13 22:25:35 +00:00
parent ba8b79e932
commit 0f8bc043c5
2 changed files with 37 additions and 17 deletions
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18
llvm/lib/Target/X86/X86FastISel.cpp
View File

@ -3163,7 +3163,8 @@ unsigned X86FastISel::X86MaterializeFP(const ConstantFP *CFP, MVT VT) {
return TargetMaterializeFloatZero(CFP);
// Can't handle alternate code models yet.
if (TM.getCodeModel() != CodeModel::Small)
CodeModel::Model CM = TM.getCodeModel();
if (CM != CodeModel::Small && CM != CodeModel::Large)
return 0;
// Get opcode and regclass of the output for the given load instruction.
@ -3219,6 +3220,21 @@ unsigned X86FastISel::X86MaterializeFP(const ConstantFP *CFP, MVT VT) {
unsigned CPI = MCP.getConstantPoolIndex(CFP, Align);
unsigned ResultReg = createResultReg(RC);
if (CM == CodeModel::Large) {
unsigned AddrReg = createResultReg(&X86::GR64RegClass);
BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(X86::MOV64ri),
AddrReg)
.addConstantPoolIndex(CPI, 0, OpFlag);
MachineInstrBuilder MIB = BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
TII.get(Opc), ResultReg);
addDirectMem(MIB, AddrReg);
MachineMemOperand *MMO = FuncInfo.MF->getMachineMemOperand(
MachinePointerInfo::getConstantPool(), MachineMemOperand::MOLoad,
TM.getSubtargetImpl()->getDataLayout()->getPointerSize(), Align);
MIB->addMemOperand(*FuncInfo.MF, MMO);
return ResultReg;
}
addConstantPoolReference(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
TII.get(Opc), ResultReg),
CPI, PICBase, OpFlag);

36
llvm/test/CodeGen/X86/fast-isel-constpool.ll
View File

@ -1,19 +1,23 @@
; RUN: llc < %s -fast-isel | FileCheck %s
; CHECK: LCPI0_0(%rip)
; RUN: llc -mtriple=x86_64-apple-darwin -fast-isel -code-model=small < %s | FileCheck %s
; RUN: llc -mtriple=x86_64-apple-darwin -fast-isel -code-model=large < %s | FileCheck %s --check-prefix=LARGE
; Make sure fast isel uses rip-relative addressing when required.
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"
target triple = "x86_64-apple-darwin9.0"
; Make sure fast isel uses rip-relative addressing for the small code model.
define float @constpool_float(float %x) {
; CHECK-LABEL: constpool_float
; CHECK: LCPI0_0(%rip)
define i32 @f0(double %x) nounwind {
entry:
%retval = alloca i32 ; <i32*> [#uses=2]
%x.addr = alloca double ; <double*> [#uses=2]
store double %x, double* %x.addr
%tmp = load double* %x.addr ; <double> [#uses=1]
%cmp = fcmp olt double %tmp, 8.500000e-01 ; <i1> [#uses=1]
%conv = zext i1 %cmp to i32 ; <i32> [#uses=1]
store i32 %conv, i32* %retval
%0 = load i32* %retval ; <i32> [#uses=1]
ret i32 %0
; LARGE-LABEL: constpool_float
; LARGE: movabsq $LCPI0_0, %rax
%1 = fadd float %x, 16.50e+01
ret float %1
}
define double @constpool_double(double %x) nounwind {
; CHECK-LABEL: constpool_double
; CHECK: LCPI1_0(%rip)
; LARGE-LABEL: constpool_double
; LARGE: movabsq $LCPI1_0, %rax
%1 = fadd double %x, 8.500000e-01
ret double %1
}