[FPEnv] Use single enum to represent rounding mode
Now compiler defines 5 sets of constants to represent rounding mode.
These are:
1. `llvm::APFloatBase::roundingMode`. It specifies all 5 rounding modes
defined by IEEE-754 and is used in `APFloat` implementation.
2. `clang::LangOptions::FPRoundingModeKind`. It specifies 4 of 5 IEEE-754
rounding modes and a special value for dynamic rounding mode. It is used
in clang frontend.
3. `llvm::fp::RoundingMode`. Defines the same values as
`clang::LangOptions::FPRoundingModeKind` but in different order. It is
used to specify rounding mode in in IR and functions that operate IR.
4. Rounding mode representation used by `FLT_ROUNDS` (C11, 5.2.4.2.2p7).
Besides constants for rounding mode it also uses a special value to
indicate error. It is convenient to use in intrinsic functions, as it
represents platform-independent representation for rounding mode. In this
role it is used in some pending patches.
5. Values like `FE_DOWNWARD` and other, which specify rounding mode in
library calls `fesetround` and `fegetround`. Often they represent bits
of some control register, so they are target-dependent. The same names
(not values) and a special name `FE_DYNAMIC` are used in
`#pragma STDC FENV_ROUND`.
The first 4 sets of constants are target independent and could have the
same numerical representation. It would simplify conversion between the
representations. Also now `clang::LangOptions::FPRoundingModeKind` and
`llvm::fp::RoundingMode` do not contain the value for IEEE-754 rounding
direction `roundTiesToAway`, although it is supported natively on
some targets.
This change defines all the rounding mode type via one `llvm::RoundingMode`,
which also contains rounding mode for IEEE rounding direction `roundTiesToAway`.
Differential Revision: https://reviews.llvm.org/D77379
diff --git a/llvm/lib/IR/FPEnv.cpp b/llvm/lib/IR/FPEnv.cpp
index ab68f55..40f999e 100644
--- a/llvm/lib/IR/FPEnv.cpp
+++ b/llvm/lib/IR/FPEnv.cpp
@@ -17,36 +17,42 @@
namespace llvm {
-Optional<fp::RoundingMode> StrToRoundingMode(StringRef RoundingArg) {
+Optional<RoundingMode> StrToRoundingMode(StringRef RoundingArg) {
// For dynamic rounding mode, we use round to nearest but we will set the
// 'exact' SDNodeFlag so that the value will not be rounded.
- return StringSwitch<Optional<fp::RoundingMode>>(RoundingArg)
- .Case("round.dynamic", fp::rmDynamic)
- .Case("round.tonearest", fp::rmToNearest)
- .Case("round.downward", fp::rmDownward)
- .Case("round.upward", fp::rmUpward)
- .Case("round.towardzero", fp::rmTowardZero)
+ return StringSwitch<Optional<RoundingMode>>(RoundingArg)
+ .Case("round.dynamic", RoundingMode::Dynamic)
+ .Case("round.tonearest", RoundingMode::NearestTiesToEven)
+ .Case("round.tonearestaway", RoundingMode::NearestTiesToAway)
+ .Case("round.downward", RoundingMode::TowardNegative)
+ .Case("round.upward", RoundingMode::TowardPositive)
+ .Case("round.towardzero", RoundingMode::TowardZero)
.Default(None);
}
-Optional<StringRef> RoundingModeToStr(fp::RoundingMode UseRounding) {
+Optional<StringRef> RoundingModeToStr(RoundingMode UseRounding) {
Optional<StringRef> RoundingStr = None;
switch (UseRounding) {
- case fp::rmDynamic:
+ case RoundingMode::Dynamic:
RoundingStr = "round.dynamic";
break;
- case fp::rmToNearest:
+ case RoundingMode::NearestTiesToEven:
RoundingStr = "round.tonearest";
break;
- case fp::rmDownward:
+ case RoundingMode::NearestTiesToAway:
+ RoundingStr = "round.tonearestaway";
+ break;
+ case RoundingMode::TowardNegative:
RoundingStr = "round.downward";
break;
- case fp::rmUpward:
+ case RoundingMode::TowardPositive:
RoundingStr = "round.upward";
break;
- case fp::rmTowardZero:
+ case RoundingMode::TowardZero:
RoundingStr = "round.towardzero";
break;
+ default:
+ break;
}
return RoundingStr;
}
@@ -74,21 +80,4 @@
}
return ExceptStr;
}
-
-Optional<APFloatBase::roundingMode>
-getAPFloatRoundingMode(fp::RoundingMode RM) {
- switch (RM) {
- case fp::rmDynamic:
- return None;
- case fp::rmToNearest:
- return APFloat::rmNearestTiesToEven;
- case fp::rmDownward:
- return APFloat::rmTowardNegative;
- case fp::rmUpward:
- return APFloat::rmTowardPositive;
- case fp::rmTowardZero:
- return APFloat::rmTowardZero;
- }
- llvm_unreachable("Unexpected rounding mode");
-}
}