The PowerPC 128-bit long double data type (ppcf128 in LLVM) is in fact a
pair of two doubles, where one is considered the "high" or
more-significant part, and the other is considered the "low" or
less-significant part. When a ppcf128 value is stored in memory or a
register pair, the high part always comes first, i.e. at the lower
memory address or in the lower-numbered register, and the low part
always comes second. This is true both on big-endian and little-endian
PowerPC systems. (Similar to how with a complex number, the real part
always comes first and the imaginary part second, no matter the byte
order of the system.)
This was implemented incorrectly for little-endian systems in LLVM.
This commit fixes three related issues:
- When printing an immediate ppcf128 constant to assembler output
in emitGlobalConstantFP, emit the high part first on both big-
and little-endian systems.
- When lowering a ppcf128 type to a pair of f64 types in SelectionDAG
(which is used e.g. when generating code to load an argument into a
register pair), use correct low/high part ordering on little-endian
systems.
- In a related issue, because lowering ppcf128 into a pair of f64 must
operate differently from lowering an int128 into a pair of i64,
bitcasts between ppcf128 and int128 must not be optimized away by the
DAG combiner on little-endian systems, but must effect a word-swap.
Reviewed by Hal Finkel.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212274
91177308-0d34-0410-b5e6-
96231b3b80d8
/// reduce runtime.
virtual bool ShouldShrinkFPConstant(EVT) const { return true; }
+ /// When splitting a value of the specified type into parts, does the Lo
+ /// or Hi part come first? This usually follows the endianness, except
+ /// for ppcf128, where the Hi part always comes first.
+ bool hasBigEndianPartOrdering(EVT VT) const {
+ return isBigEndian() || VT == MVT::ppcf128;
+ }
+
/// If true, the target has custom DAG combine transformations that it can
/// perform for the specified node.
bool hasTargetDAGCombine(ISD::NodeType NT) const {
// PPC's long double has odd notions of endianness compared to how LLVM
// handles it: p[0] goes first for *big* endian on PPC.
- if (AP.TM.getDataLayout()->isBigEndian() != CFP->getType()->isPPC_FP128Ty()) {
+ if (AP.TM.getDataLayout()->isBigEndian() &&
+ !CFP->getType()->isPPC_FP128Ty()) {
int Chunk = API.getNumWords() - 1;
if (TrailingBytes)
if (ISD::isNormalLoad(N0.getNode()) && N0.hasOneUse() &&
// Do not change the width of a volatile load.
!cast<LoadSDNode>(N0)->isVolatile() &&
+ // Do not remove the cast if the types differ in endian layout.
+ TLI.hasBigEndianPartOrdering(N0.getValueType()) ==
+ TLI.hasBigEndianPartOrdering(VT) &&
(!LegalOperations || TLI.isOperationLegal(ISD::LOAD, VT)) &&
TLI.isLoadBitCastBeneficial(N0.getValueType(), VT)) {
LoadSDNode *LN0 = cast<LoadSDNode>(N0);
case TargetLowering::TypeExpandFloat:
// Convert the expanded pieces of the input.
GetExpandedOp(InOp, Lo, Hi);
+ if (TLI.hasBigEndianPartOrdering(InVT) !=
+ TLI.hasBigEndianPartOrdering(OutVT))
+ std::swap(Lo, Hi);
Lo = DAG.getNode(ISD::BITCAST, dl, NOutVT, Lo);
Hi = DAG.getNode(ISD::BITCAST, dl, NOutVT, Hi);
return;
case TargetLowering::TypeSplitVector:
GetSplitVector(InOp, Lo, Hi);
- if (TLI.isBigEndian())
+ if (TLI.hasBigEndianPartOrdering(OutVT))
std::swap(Lo, Hi);
Lo = DAG.getNode(ISD::BITCAST, dl, NOutVT, Lo);
Hi = DAG.getNode(ISD::BITCAST, dl, NOutVT, Hi);
EVT LoVT, HiVT;
std::tie(LoVT, HiVT) = DAG.GetSplitDestVTs(InVT);
std::tie(Lo, Hi) = DAG.SplitVector(InOp, dl, LoVT, HiVT);
- if (TLI.isBigEndian())
+ if (TLI.hasBigEndianPartOrdering(OutVT))
std::swap(Lo, Hi);
Lo = DAG.getNode(ISD::BITCAST, dl, NOutVT, Lo);
Hi = DAG.getNode(ISD::BITCAST, dl, NOutVT, Hi);
false, false, MinAlign(Alignment, IncrementSize));
// Handle endianness of the load.
- if (TLI.isBigEndian())
+ if (TLI.hasBigEndianPartOrdering(OutVT))
std::swap(Lo, Hi);
}
SDLoc dl(N);
LoadSDNode *LD = cast<LoadSDNode>(N);
- EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(), LD->getValueType(0));
+ EVT ValueVT = LD->getValueType(0);
+ EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(), ValueVT);
SDValue Chain = LD->getChain();
SDValue Ptr = LD->getBasePtr();
unsigned Alignment = LD->getAlignment();
Hi.getValue(1));
// Handle endianness of the load.
- if (TLI.isBigEndian())
+ if (TLI.hasBigEndianPartOrdering(ValueVT))
std::swap(Lo, Hi);
// Modified the chain - switch anything that used the old chain to use
Hi = DAG.getVAArg(NVT, dl, Lo.getValue(1), Ptr, N->getOperand(2), 0);
// Handle endianness of the load.
- if (TLI.isBigEndian())
+ if (TLI.hasBigEndianPartOrdering(OVT))
std::swap(Lo, Hi);
// Modified the chain - switch anything that used the old chain to use
SDLoc dl(N);
StoreSDNode *St = cast<StoreSDNode>(N);
- EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(),
- St->getValue().getValueType());
+ EVT ValueVT = St->getValue().getValueType();
+ EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(), ValueVT);
SDValue Chain = St->getChain();
SDValue Ptr = St->getBasePtr();
unsigned Alignment = St->getAlignment();
SDValue Lo, Hi;
GetExpandedOp(St->getValue(), Lo, Hi);
- if (TLI.isBigEndian())
+ if (TLI.hasBigEndianPartOrdering(ValueVT))
std::swap(Lo, Hi);
Lo = DAG.getStore(Chain, dl, Lo, Ptr, St->getPointerInfo(),
SDValue Lo, Hi;
Lo = DAG.getNode(ISD::BITCAST, DL, EVT(MVT::f64), Parts[0]);
Hi = DAG.getNode(ISD::BITCAST, DL, EVT(MVT::f64), Parts[1]);
- if (TLI.isBigEndian())
+ if (TLI.hasBigEndianPartOrdering(ValueVT))
std::swap(Lo, Hi);
Val = DAG.getNode(ISD::BUILD_PAIR, DL, ValueVT, Lo, Hi);
} else {
--- /dev/null
+; RUN: llc -mcpu=pwr7 -mattr=+altivec < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-n32:64"
+target triple = "powerpc64le-unknown-linux-gnu"
+
+@g = common global ppc_fp128 0xM00000000000000000000000000000000, align 16
+
+define void @callee(ppc_fp128 %x) {
+entry:
+ %x.addr = alloca ppc_fp128, align 16
+ store ppc_fp128 %x, ppc_fp128* %x.addr, align 16
+ %0 = load ppc_fp128* %x.addr, align 16
+ store ppc_fp128 %0, ppc_fp128* @g, align 16
+ ret void
+}
+; CHECK: @callee
+; CHECK: ld [[REG:[0-9]+]], .LC
+; CHECK: stfd 2, 8([[REG]])
+; CHECK: stfd 1, 0([[REG]])
+; CHECK: blr
+
+define void @caller() {
+entry:
+ %0 = load ppc_fp128* @g, align 16
+ call void @test(ppc_fp128 %0)
+ ret void
+}
+; CHECK: @caller
+; CHECK: ld [[REG:[0-9]+]], .LC
+; CHECK: lfd 2, 8([[REG]])
+; CHECK: lfd 1, 0([[REG]])
+; CHECK: bl test
+
+declare void @test(ppc_fp128)
+
+define void @caller_const() {
+entry:
+ call void @test(ppc_fp128 0xM3FF00000000000000000000000000000)
+ ret void
+}
+; CHECK: .LCPI[[LC:[0-9]+]]_0:
+; CHECK: .long 1065353216
+; CHECK: .LCPI[[LC]]_1:
+; CHECK: .long 0
+; CHECK: @caller_const
+; CHECK: addi [[REG0:[0-9]+]], {{[0-9]+}}, .LCPI[[LC]]_0
+; CHECK: addi [[REG1:[0-9]+]], {{[0-9]+}}, .LCPI[[LC]]_1
+; CHECK: lfs 1, 0([[REG0]])
+; CHECK: lfs 2, 0([[REG1]])
+; CHECK: bl test
+
+define ppc_fp128 @result() {
+entry:
+ %0 = load ppc_fp128* @g, align 16
+ ret ppc_fp128 %0
+}
+; CHECK: @result
+; CHECK: ld [[REG:[0-9]+]], .LC
+; CHECK: lfd 1, 0([[REG]])
+; CHECK: lfd 2, 8([[REG]])
+; CHECK: blr
+
+define void @use_result() {
+entry:
+ %call = tail call ppc_fp128 @test_result() #3
+ store ppc_fp128 %call, ppc_fp128* @g, align 16
+ ret void
+}
+; CHECK: @use_result
+; CHECK: bl test_result
+; CHECK: ld [[REG:[0-9]+]], .LC
+; CHECK: stfd 2, 8([[REG]])
+; CHECK: stfd 1, 0([[REG]])
+; CHECK: blr
+
+declare ppc_fp128 @test_result()
+
+define void @caller_result() {
+entry:
+ %call = tail call ppc_fp128 @test_result()
+ tail call void @test(ppc_fp128 %call)
+ ret void
+}
+; CHECK: @caller_result
+; CHECK: bl test_result
+; CHECK-NEXT: nop
+; CHECK-NEXT: bl test
+; CHECK-NEXT: nop
+
+define i128 @convert_from(ppc_fp128 %x) {
+entry:
+ %0 = bitcast ppc_fp128 %x to i128
+ ret i128 %0
+}
+; CHECK: @convert_from
+; CHECK: stfd 1, [[OFF1:.*]](1)
+; CHECK: stfd 2, [[OFF2:.*]](1)
+; CHECK: ld 3, [[OFF1]](1)
+; CHECK: ld 4, [[OFF2]](1)
+; CHECK: blr
+
+define ppc_fp128 @convert_to(i128 %x) {
+entry:
+ %0 = bitcast i128 %x to ppc_fp128
+ ret ppc_fp128 %0
+}
+; CHECK: @convert_to
+; CHECK: std 3, [[OFF1:.*]](1)
+; CHECK: std 4, [[OFF2:.*]](1)
+; CHECK: lfd 1, [[OFF1]](1)
+; CHECK: lfd 2, [[OFF2]](1)
+; CHECK: blr
+
+define ppc_fp128 @convert_to2(i128 %x) {
+entry:
+ %shl = shl i128 %x, 1
+ %0 = bitcast i128 %shl to ppc_fp128
+ ret ppc_fp128 %0
+}
+
+; CHECK: @convert_to
+; CHECK: std 3, [[OFF1:.*]](1)
+; CHECK: std 4, [[OFF2:.*]](1)
+; CHECK: lfd 1, [[OFF1]](1)
+; CHECK: lfd 2, [[OFF2]](1)
+; CHECK: blr
+
+define double @convert_vector(<4 x i32> %x) {
+entry:
+ %cast = bitcast <4 x i32> %x to ppc_fp128
+ %conv = fptrunc ppc_fp128 %cast to double
+ ret double %conv
+}
+; CHECK: @convert_vector
+; CHECK: addi [[REG:[0-9]+]], 1, [[OFF:.*]]
+; CHECK: stvx 2, 0, [[REG]]
+; CHECK: lfd 1, [[OFF]](1)
+; CHECK: blr
+
+declare void @llvm.va_start(i8*)
+
+define double @vararg(i32 %a, ...) {
+entry:
+ %va = alloca i8*, align 8
+ %va1 = bitcast i8** %va to i8*
+ call void @llvm.va_start(i8* %va1)
+ %arg = va_arg i8** %va, ppc_fp128
+ %conv = fptrunc ppc_fp128 %arg to double
+ ret double %conv
+}
+; CHECK: @vararg
+; CHECK: lfd 1, 0({{[0-9]+}})
+; CHECK: blr
+
; CHECK-NEXT: .size
; CHECK: varppc128:
-; CHECK-NEXT: .quad 0 # ppc_fp128 -0
-; CHECK-NEXT: .quad -9223372036854775808
+; For ppc_fp128, the high double always comes first.
+; CHECK-NEXT: .quad -9223372036854775808 # ppc_fp128 -0
+; CHECK-NEXT: .quad 0
; CHECK-NEXT: .size
; CHECK: var80:
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