zahiraam updated this revision to Diff 414460.
zahiraam marked an inline comment as done.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D121122/new/
https://reviews.llvm.org/D121122
Files:
clang/lib/Lex/PPMacroExpansion.cpp
clang/lib/Sema/Sema.cpp
clang/lib/Sema/SemaAttr.cpp
clang/test/CodeGen/eval-method-fast-math.c
Index: clang/test/CodeGen/eval-method-fast-math.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/eval-method-fast-math.c
@@ -0,0 +1,87 @@
+// 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 res;
+int add(float a, float b, float c) {
+ // CHECK: fadd float
+ // CHECK: load float, float*
+ // CHECK: fadd float
+ // CHECK: store float
+ // CHECK-FAST: fadd fast float
+ // CHECK-FAST: load float, float*
+ // CHECK-FAST: fadd fast float
+ // CHECK: ret i32 0
+ // CHECK-EXT: ret i32 2
+ // CHECK-FAST: ret i32 -1
+ 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
+ // CHECK-FAST: ret i32 -1
+ 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
+ // CHECK-FAST: ret i32 -1
+ 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-FAST: fadd fast float
+ // CHECK-FAST: load float, float*
+ // CHECK-FAST: fadd fast float
+ // CHECK-FAST: 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-FAST: fadd fast float
+ // CHECK-FAST: load float, float*
+ // CHECK-FAST: fadd fast float
+ // CHECK-FAST: 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__;
+}
Index: clang/lib/Sema/SemaAttr.cpp
===================================================================
--- clang/lib/Sema/SemaAttr.cpp
+++ clang/lib/Sema/SemaAttr.cpp
@@ -517,6 +517,9 @@
else
NewFPFeatures.setFPPreciseEnabled(false);
FpPragmaStack.Act(Loc, Action, StringRef(), NewFPFeatures);
+ // `AllowFPReassoc` or `AllowReciprocal` option is enabled.
+ PP.setCurrentFPEvalMethod(
+ Loc, LangOptions::FPEvalMethodKind::FEM_Indeterminable);
break;
case PFC_Except:
if (!isPreciseFPEnabled())
@@ -540,6 +543,12 @@
}
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
@@ -254,6 +254,12 @@
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 these, 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[]>(2);
+ 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.
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