zahiraam updated this revision to Diff 416180.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D121122/new/
https://reviews.llvm.org/D121122
Files:
clang/include/clang/Lex/Preprocessor.h
clang/lib/Lex/PPMacroExpansion.cpp
clang/lib/Sema/Sema.cpp
clang/lib/Sema/SemaAttr.cpp
clang/test/CodeGen/eval-method-fast-math.cpp
Index: clang/test/CodeGen/eval-method-fast-math.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGen/eval-method-fast-math.cpp
@@ -0,0 +1,117 @@
+// RUN: %clang_cc1 -fexperimental-strict-floating-point \
+// RUN: -triple x86_64-linux-gnu -emit-llvm -o - %s \
+// RUN: | FileCheck %s -check-prefixes=CHECK
+
+// RUN: %clang_cc1 -triple i386--linux -emit-llvm -o - %s \
+// RUN: | FileCheck %s -check-prefixes=CHECK-EXT
+
+// RUN: %clang_cc1 -fexperimental-strict-floating-point \
+// RUN: -mreassociate -freciprocal-math -ffp-contract=fast \
+// RUN: -ffast-math -triple x86_64-linux-gnu \
+// RUN: -emit-llvm -o - %s \
+// RUN: | FileCheck %s -check-prefixes=CHECK-FAST
+
+// RUN: %clang_cc1 -triple i386--linux -mreassociate -freciprocal-math \
+// RUN: -ffp-contract=fast -ffast-math -emit-llvm -o - %s \
+// RUN: | FileCheck %s -check-prefixes=CHECK-FAST
+
+float a = 1.0f, b = 2.0f, c = 3.0f;
+#pragma float_control(precise, off)
+float res2 = a + b + c;
+int val3 = __FLT_EVAL_METHOD__;
+#pragma float_control(precise, on)
+float res3 = a + b + c;
+int val4 = __FLT_EVAL_METHOD__;
+
+// CHECK: @val3 = global i32 -1
+// CHECK: @val4 = global i32 0
+
+// CHECK-EXT: @val3 = global i32 -1
+// CHECK-EXT: @val4 = global i32 2
+
+// CHECK-FAST: @val3 = global i32 -1
+// CHECK-FAST: @val4 = global i32 -1
+
+float res;
+int add(float a, float b, float c) {
+ // CHECK: fadd float
+ // CHECK: load float, float*
+ // CHECK: fadd float
+ // CHECK: store float
+ // CHECK: ret i32 0
+ res = a + b + c;
+ return __FLT_EVAL_METHOD__;
+}
+
+int add_precise(float a, float b, float c) {
+#pragma float_control(precise, on)
+ // CHECK: fadd float
+ // CHECK: load float, float*
+ // CHECK: fadd float
+ // CHECK: store float
+ // CHECK: ret i32 0
+ res = a + b + c;
+ return __FLT_EVAL_METHOD__;
+}
+
+#pragma float_control(push)
+#pragma float_control(precise, on)
+int add_precise_1(float a, float b, float c) {
+ // CHECK: fadd float
+ // CHECK: load float, float*
+ // CHECK: fadd float
+ // CHECK: store float
+ // CHECK: ret i32 0
+ res = a + b + c;
+ return __FLT_EVAL_METHOD__;
+}
+#pragma float_control(pop)
+
+int add_not_precise(float a, float b, float c) {
+ // Fast-math is enabled with this pragma.
+#pragma float_control(precise, off)
+ // CHECK: fadd fast float
+ // CHECK: load float, float*
+ // CHECK: fadd fast float
+ // CHECK: float {{.*}}, float*
+ // CHECK: ret i32 -1
+ res = a + b + c;
+ return __FLT_EVAL_METHOD__;
+}
+
+#pragma float_control(push)
+// Fast-math is enabled with this pragma.
+#pragma float_control(precise, off)
+int add_not_precise_1(float a, float b, float c) {
+ // CHECK: fadd fast float
+ // CHECK: load float, float*
+ // CHECK: fadd fast float
+ // CHECK: float {{.*}}, float*
+ // CHECK: ret i32 -1
+ res = a + b + c;
+ return __FLT_EVAL_METHOD__;
+}
+#pragma float_control(pop)
+
+int getFPEvalMethod() {
+ // CHECK: ret i32 0
+ return __FLT_EVAL_METHOD__;
+}
+
+float res1;
+int whatever(float a, float b, float c) {
+#pragma float_control(precise, off)
+ // CHECK: load float, float*
+ // CHECK: fadd fast float
+ // CHECK: store float {{.*}}, float*
+ // CHECK: store i32 -1
+ // CHECK: store i32 0
+ // CHECK: ret i32 -1
+ res1 = a + b + c;
+ int val1 = __FLT_EVAL_METHOD__;
+ {
+#pragma float_control(precise, on)
+ int val2 = __FLT_EVAL_METHOD__;
+ }
+ return __FLT_EVAL_METHOD__;
+}
Index: clang/lib/Sema/SemaAttr.cpp
===================================================================
--- clang/lib/Sema/SemaAttr.cpp
+++ clang/lib/Sema/SemaAttr.cpp
@@ -508,6 +508,13 @@
case PFC_Precise:
NewFPFeatures.setFPPreciseEnabled(true);
FpPragmaStack.Act(Loc, Action, StringRef(), NewFPFeatures);
+ if (PP.getCurrentFPEvalMethod() ==
+ LangOptions::FPEvalMethodKind::FEM_Indeterminable &&
+ PP.getLastFPEvalPragmaLocation().isValid())
+ // A preceding `pragma float_control(precise,off)` has changed
+ // the value of the evaluation method.
+ // Set it back to its old value.
+ PP.setCurrentFPEvalMethod(SourceLocation(), PP.getLastFPEvalMethod());
break;
case PFC_NoPrecise:
if (CurFPFeatures.getFPExceptionMode() == LangOptions::FPE_Strict)
@@ -517,6 +524,10 @@
else
NewFPFeatures.setFPPreciseEnabled(false);
FpPragmaStack.Act(Loc, Action, StringRef(), NewFPFeatures);
+ PP.setLastFPEvalMethod(PP.getCurrentFPEvalMethod());
+ // `AllowFPReassoc` or `AllowReciprocal` option is enabled.
+ PP.setCurrentFPEvalMethod(
+ Loc, LangOptions::FPEvalMethodKind::FEM_Indeterminable);
break;
case PFC_Except:
if (!isPreciseFPEnabled())
@@ -540,6 +551,12 @@
}
FpPragmaStack.Act(Loc, Action, StringRef(), NewFPFeatures);
NewFPFeatures = FpPragmaStack.CurrentValue;
+ if (CurFPFeatures.getAllowFPReassociate() ||
+ CurFPFeatures.getAllowReciprocal())
+ // Since we are popping the pragma, we don't want to be passing
+ // a location here.
+ PP.setCurrentFPEvalMethod(SourceLocation(),
+ CurFPFeatures.getFPEvalMethod());
break;
}
CurFPFeatures = NewFPFeatures.applyOverrides(getLangOpts());
Index: clang/lib/Sema/Sema.cpp
===================================================================
--- clang/lib/Sema/Sema.cpp
+++ clang/lib/Sema/Sema.cpp
@@ -257,6 +257,12 @@
PP.setCurrentFPEvalMethod(SourceLocation(),
getLangOpts().getFPEvalMethod());
CurFPFeatures.setFPEvalMethod(PP.getCurrentFPEvalMethod());
+ // When `-ffast-math` option is enabled, it triggers several driver math
+ // options to be enabled. Among those, only one the following two modes
+ // affect the eval-method: reciprocal or reassociate.
+ if (getLangOpts().AllowFPReassoc || getLangOpts().AllowRecip)
+ PP.setCurrentFPEvalMethod(SourceLocation(),
+ LangOptions::FEM_Indeterminable);
}
// Anchor Sema's type info to this TU.
Index: clang/lib/Lex/PPMacroExpansion.cpp
===================================================================
--- clang/lib/Lex/PPMacroExpansion.cpp
+++ clang/lib/Lex/PPMacroExpansion.cpp
@@ -1577,14 +1577,35 @@
Tok.setKind(tok::string_literal);
} else if (II == Ident__FLT_EVAL_METHOD__) {
// __FLT_EVAL_METHOD__ is set to the default value.
- OS << getTUFPEvalMethod();
- // __FLT_EVAL_METHOD__ expands to a simple numeric value.
- Tok.setKind(tok::numeric_constant);
- if (getLastFPEvalPragmaLocation().isValid()) {
- // The program is ill-formed. The value of __FLT_EVAL_METHOD__ is altered
- // by the pragma.
- Diag(Tok, diag::err_illegal_use_of_flt_eval_macro);
- Diag(getLastFPEvalPragmaLocation(), diag::note_pragma_entered_here);
+ if (getTUFPEvalMethod() ==
+ LangOptions::FPEvalMethodKind::FEM_Indeterminable) {
+ // This is possible if `AllowFPReassoc` or `AllowReciprocal` is enabled.
+ // These modes can be triggered via the command line option `-ffast-math`
+ // or via a `pragam float_control`.
+ // __FLT_EVAL_METHOD__ expands to -1.
+ // The `minus` operator is the next token we read from the stream.
+ auto Toks = std::make_unique<Token[]>(1);
+ OS << "-";
+ Tok.setKind(tok::minus);
+ // Push the token `1` to the stream.
+ Token NumberToken;
+ NumberToken.startToken();
+ NumberToken.setKind(tok::numeric_constant);
+ NumberToken.setLiteralData("1");
+ NumberToken.setLength(1);
+ Toks[0] = NumberToken;
+ EnterTokenStream(std::move(Toks), 1, /*DisableMacroExpansion*/ false,
+ /*IsReinject*/ false);
+ } else {
+ OS << getTUFPEvalMethod();
+ // __FLT_EVAL_METHOD__ expands to a simple numeric value.
+ Tok.setKind(tok::numeric_constant);
+ if (getLastFPEvalPragmaLocation().isValid()) {
+ // The program is ill-formed. The value of __FLT_EVAL_METHOD__ is
+ // altered by the pragma.
+ Diag(Tok, diag::err_illegal_use_of_flt_eval_macro);
+ Diag(getLastFPEvalPragmaLocation(), diag::note_pragma_entered_here);
+ }
}
} else if (II == Ident__COUNTER__) {
// __COUNTER__ expands to a simple numeric value.
Index: clang/include/clang/Lex/Preprocessor.h
===================================================================
--- clang/include/clang/Lex/Preprocessor.h
+++ clang/include/clang/Lex/Preprocessor.h
@@ -192,6 +192,11 @@
LangOptions::FPEvalMethodKind CurrentFPEvalMethod =
LangOptions::FPEvalMethodKind::FEM_UnsetOnCommandLine;
+ // Keeps the value of the last evaluation method before a
+ // `pragma float_control (precise,off) is applied.
+ LangOptions::FPEvalMethodKind LastFPEvalMethod =
+ LangOptions::FPEvalMethodKind::FEM_UnsetOnCommandLine;
+
// The most recent pragma location where the floating point evaluation
// method was modified. This is used to determine whether the
// 'pragma clang fp eval_method' was used whithin the current scope.
@@ -2078,6 +2083,14 @@
return LastFPEvalPragmaLocation;
}
+ LangOptions::FPEvalMethodKind getLastFPEvalMethod() const {
+ return LastFPEvalMethod;
+ }
+
+ void setLastFPEvalMethod(LangOptions::FPEvalMethodKind Val) {
+ LastFPEvalMethod = Val;
+ }
+
void setCurrentFPEvalMethod(SourceLocation PragmaLoc,
LangOptions::FPEvalMethodKind Val) {
assert(Val != LangOptions::FEM_UnsetOnCommandLine &&
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