hokein updated this revision to Diff 249606.
hokein added a comment.
reduce FPOption from 8 bits to 7 bits, based on the offline discussion.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D75443/new/
https://reviews.llvm.org/D75443
Files:
clang/include/clang/AST/Stmt.h
clang/include/clang/Basic/LangOptions.h
Index: clang/include/clang/Basic/LangOptions.h
===================================================================
--- clang/include/clang/Basic/LangOptions.h
+++ clang/include/clang/Basic/LangOptions.h
@@ -197,7 +197,7 @@
/// Possible rounding modes.
enum FPRoundingModeKind {
/// Rounding to nearest, corresponds to "round.tonearest".
- FPR_ToNearest,
+ FPR_ToNearest = 0,
/// Rounding toward -Inf, corresponds to "round.downward".
FPR_Downward,
/// Rounding toward +Inf, corresponds to "round.upward".
@@ -211,7 +211,7 @@
/// Possible floating point exception behavior.
enum FPExceptionModeKind {
/// Assume that floating-point exceptions are masked.
- FPE_Ignore,
+ FPE_Ignore = 0,
/// Transformations do not cause new exceptions but may hide some.
FPE_MayTrap,
/// Strictly preserve the floating-point exception semantics.
@@ -358,23 +358,20 @@
public:
FPOptions() : fp_contract(LangOptions::FPC_Off),
fenv_access(LangOptions::FEA_Off),
- rounding(LangOptions::FPR_ToNearest),
- exceptions(LangOptions::FPE_Ignore)
+ packed(0)
{}
// Used for serializing.
explicit FPOptions(unsigned I)
: fp_contract(static_cast<LangOptions::FPContractModeKind>(I & 3)),
fenv_access(static_cast<LangOptions::FEnvAccessModeKind>((I >> 2) & 1)),
- rounding(static_cast<LangOptions::FPRoundingModeKind>((I >> 3) & 7)),
- exceptions(static_cast<LangOptions::FPExceptionModeKind>((I >> 6) & 3))
+ packed(I >> 3)
{}
explicit FPOptions(const LangOptions &LangOpts)
: fp_contract(LangOpts.getDefaultFPContractMode()),
fenv_access(LangOptions::FEA_Off),
- rounding(LangOptions::FPR_ToNearest),
- exceptions(LangOptions::FPE_Ignore)
+ packed(0)
{}
// FIXME: Use getDefaultFEnvAccessMode() when available.
@@ -407,19 +404,24 @@
void setDisallowFEnvAccess() { fenv_access = LangOptions::FEA_Off; }
LangOptions::FPRoundingModeKind getRoundingMode() const {
+ unsigned rounding = packed / MaxExceptionValue;
return static_cast<LangOptions::FPRoundingModeKind>(rounding);
}
void setRoundingMode(LangOptions::FPRoundingModeKind RM) {
- rounding = RM;
+ packed = RM * MaxExceptionValue + getExceptionMode();
}
LangOptions::FPExceptionModeKind getExceptionMode() const {
+ static_assert(LangOptions::FPExceptionModeKind::FPE_Strict <
+ MaxExceptionValue,
+ "Max exception value must less than 3");
+ unsigned exceptions = packed % MaxExceptionValue;
return static_cast<LangOptions::FPExceptionModeKind>(exceptions);
}
void setExceptionMode(LangOptions::FPExceptionModeKind EM) {
- exceptions = EM;
+ packed = getRoundingMode() * MaxExceptionValue + EM;
}
bool isFPConstrained() const {
@@ -430,8 +432,7 @@
/// Used to serialize this.
unsigned getInt() const {
- return fp_contract | (fenv_access << 2) | (rounding << 3)
- | (exceptions << 6);
+ return fp_contract | (fenv_access << 2) | (packed << 3);
}
private:
@@ -440,8 +441,10 @@
/// of these fields.
unsigned fp_contract : 2;
unsigned fenv_access : 1;
- unsigned rounding : 3;
- unsigned exceptions : 2;
+ // A packed field for encoding rounding and exceptions.
+ // packed = MaxExceptionBits * rounding + excpetions.
+ constexpr static unsigned MaxExceptionValue = 3;
+ unsigned packed: 4;
};
/// Describes the kind of translation unit being processed.
Index: clang/include/clang/AST/Stmt.h
===================================================================
--- clang/include/clang/AST/Stmt.h
+++ clang/include/clang/AST/Stmt.h
@@ -531,7 +531,7 @@
/// This is only meaningful for operations on floating point
/// types and 0 otherwise.
- unsigned FPFeatures : 8;
+ unsigned FPFeatures : 7;
SourceLocation OpLoc;
};
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