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[ConstProp] allow folding for fma that produces NaN 

Folding for fma/fmuladd was added here:
rL202914
...and as seen in existing/unchanged tests, that works to propagate NaN
if it's already an input, but we should fold an fma() that creates NaN too.

From IEEE-754-2008 7.2 "Invalid Operation", there are 2 clauses that apply
to fma, so I added tests for those patterns:

  c) fusedMultiplyAdd: fusedMultiplyAdd(0, ∞, c) or fusedMultiplyAdd(∞, 0, c)
     unless c is a quiet NaN; if c is a quiet NaN then it is implementation
     defined whether the invalid operation exception is signaled
  d) addition or subtraction or fusedMultiplyAdd: magnitude subtraction of
     infinities, such as: addition(+∞, −∞)

Differential Revision: https://reviews.llvm.org/D67446

llvm-svn: 371735
This commit is contained in:
Sanjay Patel 2019-09-12 14:10:50 +00:00
parent 03a111dc46
commit 3f5a808365
3 changed files with 20 additions and 32 deletions
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5
llvm/include/llvm/ADT/APFloat.h
View File

@ -192,6 +192,11 @@ struct APFloatBase {
/// IEEE-754R 7: Default exception handling. /// IEEE-754R 7: Default exception handling.
/// ///
/// opUnderflow or opOverflow are always returned or-ed with opInexact. /// opUnderflow or opOverflow are always returned or-ed with opInexact.
///
/// APFloat models this behavior specified by IEEE-754:
/// "For operations producing results in floating-point format, the default
/// result of an operation that signals the invalid operation exception
/// shall be a quiet NaN."
enum opStatus { enum opStatus {
opOK = 0x00, opOK = 0x00,
opInvalidOp = 0x01, opInvalidOp = 0x01,

10
llvm/lib/Analysis/ConstantFolding.cpp
View File

@ -2243,13 +2243,9 @@ static Constant *ConstantFoldScalarCall3(StringRef Name,
case Intrinsic::fma: case Intrinsic::fma:
case Intrinsic::fmuladd: { case Intrinsic::fmuladd: {
APFloat V = Op1->getValueAPF(); APFloat V = Op1->getValueAPF();
APFloat::opStatus s = V.fusedMultiplyAdd(Op2->getValueAPF(), V.fusedMultiplyAdd(Op2->getValueAPF(), Op3->getValueAPF(),
Op3->getValueAPF(), APFloat::rmNearestTiesToEven);
APFloat::rmNearestTiesToEven); return ConstantFP::get(Ty->getContext(), V);
if (s != APFloat::opInvalidOp)
return ConstantFP::get(Ty->getContext(), V);
return nullptr;
} }
} }
} }

37
llvm/test/Transforms/ConstProp/fma.ll
View File

@ -129,8 +129,7 @@ define double @test_Inf_4() {
define double @inf_product_opposite_inf_addend_1() { define double @inf_product_opposite_inf_addend_1() {
; CHECK-LABEL: @inf_product_opposite_inf_addend_1( ; CHECK-LABEL: @inf_product_opposite_inf_addend_1(
; CHECK-NEXT: [[TMP1:%.*]] = call double @llvm.fma.f64(double 7.000000e+00, double 0xFFF0000000000000, double 0x7FF0000000000000) ; CHECK-NEXT: ret double 0x7FF8000000000000
; CHECK-NEXT: ret double [[TMP1]]
; ;
%1 = call double @llvm.fma.f64(double 7.0, double 0xFFF0000000000000, double 0x7FF0000000000000) %1 = call double @llvm.fma.f64(double 7.0, double 0xFFF0000000000000, double 0x7FF0000000000000)
ret double %1 ret double %1
@ -140,8 +139,7 @@ define double @inf_product_opposite_inf_addend_1() {
define double @inf_product_opposite_inf_addend_2() { define double @inf_product_opposite_inf_addend_2() {
; CHECK-LABEL: @inf_product_opposite_inf_addend_2( ; CHECK-LABEL: @inf_product_opposite_inf_addend_2(
; CHECK-NEXT: [[TMP1:%.*]] = call double @llvm.fma.f64(double 7.000000e+00, double 0x7FF0000000000000, double 0xFFF0000000000000) ; CHECK-NEXT: ret double 0x7FF8000000000000
; CHECK-NEXT: ret double [[TMP1]]
; ;
%1 = call double @llvm.fma.f64(double 7.0, double 0x7FF0000000000000, double 0xFFF0000000000000) %1 = call double @llvm.fma.f64(double 7.0, double 0x7FF0000000000000, double 0xFFF0000000000000)
ret double %1 ret double %1
@ -151,8 +149,7 @@ define double @inf_product_opposite_inf_addend_2() {
define double @inf_product_opposite_inf_addend_3() { define double @inf_product_opposite_inf_addend_3() {
; CHECK-LABEL: @inf_product_opposite_inf_addend_3( ; CHECK-LABEL: @inf_product_opposite_inf_addend_3(
; CHECK-NEXT: [[TMP1:%.*]] = call double @llvm.fma.f64(double 0xFFF0000000000000, double 4.200000e+01, double 0x7FF0000000000000) ; CHECK-NEXT: ret double 0x7FF8000000000000
; CHECK-NEXT: ret double [[TMP1]]
; ;
%1 = call double @llvm.fma.f64(double 0xFFF0000000000000, double 42.0, double 0x7FF0000000000000) %1 = call double @llvm.fma.f64(double 0xFFF0000000000000, double 42.0, double 0x7FF0000000000000)
ret double %1 ret double %1
@ -162,8 +159,7 @@ define double @inf_product_opposite_inf_addend_3() {
define double @inf_product_opposite_inf_addend_4() { define double @inf_product_opposite_inf_addend_4() {
; CHECK-LABEL: @inf_product_opposite_inf_addend_4( ; CHECK-LABEL: @inf_product_opposite_inf_addend_4(
; CHECK-NEXT: [[TMP1:%.*]] = call double @llvm.fma.f64(double 0x7FF0000000000000, double 4.200000e+01, double 0xFFF0000000000000) ; CHECK-NEXT: ret double 0x7FF8000000000000
; CHECK-NEXT: ret double [[TMP1]]
; ;
%1 = call double @llvm.fma.f64(double 0x7FF0000000000000, double 42.0, double 0xFFF0000000000000) %1 = call double @llvm.fma.f64(double 0x7FF0000000000000, double 42.0, double 0xFFF0000000000000)
ret double %1 ret double %1
@ -173,8 +169,7 @@ define double @inf_product_opposite_inf_addend_4() {
define double @inf_times_zero_1() { define double @inf_times_zero_1() {
; CHECK-LABEL: @inf_times_zero_1( ; CHECK-LABEL: @inf_times_zero_1(
; CHECK-NEXT: [[TMP1:%.*]] = call double @llvm.fma.f64(double 0.000000e+00, double 0xFFF0000000000000, double 4.200000e+01) ; CHECK-NEXT: ret double 0x7FF8000000000000
; CHECK-NEXT: ret double [[TMP1]]
; ;
%1 = call double @llvm.fma.f64(double 0.0, double 0xFFF0000000000000, double 42.0) %1 = call double @llvm.fma.f64(double 0.0, double 0xFFF0000000000000, double 42.0)
ret double %1 ret double %1
@ -184,8 +179,7 @@ define double @inf_times_zero_1() {
define double @inf_times_zero_2() { define double @inf_times_zero_2() {
; CHECK-LABEL: @inf_times_zero_2( ; CHECK-LABEL: @inf_times_zero_2(
; CHECK-NEXT: [[TMP1:%.*]] = call double @llvm.fma.f64(double 0.000000e+00, double 0x7FF0000000000000, double 4.200000e+01) ; CHECK-NEXT: ret double 0x7FF8000000000000
; CHECK-NEXT: ret double [[TMP1]]
; ;
%1 = call double @llvm.fma.f64(double 0.0, double 0x7FF0000000000000, double 42.0) %1 = call double @llvm.fma.f64(double 0.0, double 0x7FF0000000000000, double 42.0)
ret double %1 ret double %1
@ -195,8 +189,7 @@ define double @inf_times_zero_2() {
define double @inf_times_zero_3() { define double @inf_times_zero_3() {
; CHECK-LABEL: @inf_times_zero_3( ; CHECK-LABEL: @inf_times_zero_3(
; CHECK-NEXT: [[TMP1:%.*]] = call double @llvm.fma.f64(double 0xFFF0000000000000, double 0.000000e+00, double 4.200000e+01) ; CHECK-NEXT: ret double 0x7FF8000000000000
; CHECK-NEXT: ret double [[TMP1]]
; ;
%1 = call double @llvm.fma.f64(double 0xFFF0000000000000, double 0.0, double 42.0) %1 = call double @llvm.fma.f64(double 0xFFF0000000000000, double 0.0, double 42.0)
ret double %1 ret double %1
@ -206,8 +199,7 @@ define double @inf_times_zero_3() {
define double @inf_times_zero_4() { define double @inf_times_zero_4() {
; CHECK-LABEL: @inf_times_zero_4( ; CHECK-LABEL: @inf_times_zero_4(
; CHECK-NEXT: [[TMP1:%.*]] = call double @llvm.fma.f64(double 0x7FF0000000000000, double 0.000000e+00, double 4.200000e+01) ; CHECK-NEXT: ret double 0x7FF8000000000000
; CHECK-NEXT: ret double [[TMP1]]
; ;
%1 = call double @llvm.fma.f64(double 0x7FF0000000000000, double 0.0, double 42.0) %1 = call double @llvm.fma.f64(double 0x7FF0000000000000, double 0.0, double 42.0)
ret double %1 ret double %1
@ -217,8 +209,7 @@ define double @inf_times_zero_4() {
define double @inf_times_zero_5() { define double @inf_times_zero_5() {
; CHECK-LABEL: @inf_times_zero_5( ; CHECK-LABEL: @inf_times_zero_5(
; CHECK-NEXT: [[TMP1:%.*]] = call double @llvm.fma.f64(double -0.000000e+00, double 0xFFF0000000000000, double 4.200000e+01) ; CHECK-NEXT: ret double 0x7FF8000000000000
; CHECK-NEXT: ret double [[TMP1]]
; ;
%1 = call double @llvm.fma.f64(double -0.0, double 0xFFF0000000000000, double 42.0) %1 = call double @llvm.fma.f64(double -0.0, double 0xFFF0000000000000, double 42.0)
ret double %1 ret double %1
@ -228,8 +219,7 @@ define double @inf_times_zero_5() {
define double @inf_times_zero_6() { define double @inf_times_zero_6() {
; CHECK-LABEL: @inf_times_zero_6( ; CHECK-LABEL: @inf_times_zero_6(
; CHECK-NEXT: [[TMP1:%.*]] = call double @llvm.fma.f64(double -0.000000e+00, double 0x7FF0000000000000, double 4.200000e+01) ; CHECK-NEXT: ret double 0x7FF8000000000000
; CHECK-NEXT: ret double [[TMP1]]
; ;
%1 = call double @llvm.fma.f64(double -0.0, double 0x7FF0000000000000, double 42.0) %1 = call double @llvm.fma.f64(double -0.0, double 0x7FF0000000000000, double 42.0)
ret double %1 ret double %1
@ -239,8 +229,7 @@ define double @inf_times_zero_6() {
define double @inf_times_zero_7() { define double @inf_times_zero_7() {
; CHECK-LABEL: @inf_times_zero_7( ; CHECK-LABEL: @inf_times_zero_7(
; CHECK-NEXT: [[TMP1:%.*]] = call double @llvm.fma.f64(double 0xFFF0000000000000, double -0.000000e+00, double 4.200000e+01) ; CHECK-NEXT: ret double 0x7FF8000000000000
; CHECK-NEXT: ret double [[TMP1]]
; ;
%1 = call double @llvm.fma.f64(double 0xFFF0000000000000, double -0.0, double 42.0) %1 = call double @llvm.fma.f64(double 0xFFF0000000000000, double -0.0, double 42.0)
ret double %1 ret double %1
@ -250,10 +239,8 @@ define double @inf_times_zero_7() {
define double @inf_times_zero_8() { define double @inf_times_zero_8() {
; CHECK-LABEL: @inf_times_zero_8( ; CHECK-LABEL: @inf_times_zero_8(
; CHECK-NEXT: [[TMP1:%.*]] = call double @llvm.fma.f64(double 0x7FF0000000000000, double -0.000000e+00, double 4.200000e+01) ; CHECK-NEXT: ret double 0x7FF8000000000000
; CHECK-NEXT: ret double [[TMP1]]
; ;
%1 = call double @llvm.fma.f64(double 0x7FF0000000000000, double -0.0, double 42.0) %1 = call double @llvm.fma.f64(double 0x7FF0000000000000, double -0.0, double 42.0)
ret double %1 ret double %1
} }