[clang] 6d3b779 - Set 'rounding_mode' to 'tonearest' with '#pragma STDC FENV_ACCESS OFF'.

[Zahira Ammarguellat via cfe-commits]

Author: Zahira Ammarguellat
Date: 2023-04-12T06:44:45-04:00
New Revision: 6d3b779792fbf9ec5cc119f1812655da01020b7a

URL: https://github.com/llvm/llvm-project/commit/6d3b779792fbf9ec5cc119f1812655da01020b7a
DIFF: https://github.com/llvm/llvm-project/commit/6d3b779792fbf9ec5cc119f1812655da01020b7a.diff

LOG: Set 'rounding_mode' to 'tonearest' with '#pragma STDC FENV_ACCESS OFF'.

In strict mode the 'roundin_mode' is set to 'dynamic'. Using this pragma to
get out of strict mode doesn't have any effect on the 'rounding_mode'.
See https://godbolt.org/z/zoGTf4j1G
This patch fixes that.

Differential Revision: https://reviews.llvm.org/D147733

Added: 
    

Modified: 
    clang/lib/Sema/SemaAttr.cpp
    clang/test/CodeGen/pragma-fenv_access.c

Removed: 
    


################################################################################
diff  --git a/clang/lib/Sema/SemaAttr.cpp b/clang/lib/Sema/SemaAttr.cpp
index 0b76c041bcd7..5080b22ed507 100644
--- a/clang/lib/Sema/SemaAttr.cpp
+++ b/clang/lib/Sema/SemaAttr.cpp
@@ -1336,6 +1336,7 @@ void Sema::ActOnPragmaFEnvAccess(SourceLocation Loc, bool IsEnabled) {
       Diag(Loc, diag::err_pragma_fenv_requires_precise);
   }
   NewFPFeatures.setAllowFEnvAccessOverride(IsEnabled);
+  NewFPFeatures.setRoundingMathOverride(IsEnabled);
   FpPragmaStack.Act(Loc, PSK_Set, StringRef(), NewFPFeatures);
   CurFPFeatures = NewFPFeatures.applyOverrides(getLangOpts());
 }

diff  --git a/clang/test/CodeGen/pragma-fenv_access.c b/clang/test/CodeGen/pragma-fenv_access.c
index c986d9cff2a1..afca115ed08d 100644
--- a/clang/test/CodeGen/pragma-fenv_access.c
+++ b/clang/test/CodeGen/pragma-fenv_access.c
@@ -1,13 +1,17 @@
 // RUN: %clang_cc1 -fexperimental-strict-floating-point -ffp-exception-behavior=strict -triple %itanium_abi_triple -emit-llvm %s -o - | FileCheck --check-prefixes=CHECK,STRICT %s
+// RUN: %clang_cc1 -fexperimental-strict-floating-point -frounding-math -ffp-exception-behavior=strict -triple %itanium_abi_triple -emit-llvm %s -o - | FileCheck --check-prefixes=CHECK,STRICT-RND %s
 // RUN: %clang_cc1 -fexperimental-strict-floating-point -ffp-exception-behavior=strict -triple %itanium_abi_triple -emit-llvm %s -o - -fms-extensions -DMS | FileCheck --check-prefixes=CHECK,STRICT %s
+// RUN: %clang_cc1 -fexperimental-strict-floating-point -frounding-math -ffp-exception-behavior=strict -triple %itanium_abi_triple -emit-llvm %s -o - -fms-extensions -DMS | FileCheck --check-prefixes=CHECK,STRICT-RND %s
 // RUN: %clang_cc1 -fexperimental-strict-floating-point -triple %itanium_abi_triple -emit-llvm %s -o - | FileCheck --check-prefixes=CHECK,DEFAULT %s
-
+// RUN: %clang_cc1 -fexperimental-strict-floating-point -frounding-math -triple %itanium_abi_triple -emit-llvm %s -o - | FileCheck --check-prefixes=CHECK,DEFAULT-RND %s
 
 float func_00(float x, float y) {
   return x + y;
 }
 // CHECK-LABEL: @func_00
 // STRICT: call float @llvm.experimental.constrained.fadd.f32(float {{.*}}, float {{.*}}, metadata !"round.tonearest", metadata !"fpexcept.strict")
+// STRICT-RND: call float @llvm.experimental.constrained.fadd.f32(float {{.*}}, float {{.*}}, metadata !"round.dynamic", metadata !"fpexcept.strict")
+// DEFAULT-RND: call float @llvm.experimental.constrained.fadd.f32(float {{.*}}, float {{.*}}, metadata !"round.dynamic", metadata !"fpexcept.ignore")
 // DEFAULT: fadd float
 
 
@@ -224,3 +228,17 @@ float func_18(float x, float y) {
 // STRICT: call float @llvm.experimental.constrained.fadd.f32(float {{.*}}, float {{.*}}, metadata !"round.tonearest", metadata !"fpexcept.strict")
 // DEFAULT: fadd float
 
+#pragma STDC FENV_ACCESS ON
+float func_19(float x, float y) {
+  return x + y;
+}
+// CHECK-LABEL: @func_19
+// STRICT:  call float @llvm.experimental.constrained.fadd.f32(float {{.*}}, float {{.*}}, metadata !"round.dynamic", metadata !"fpexcept.strict")
+
+#pragma STDC FENV_ACCESS OFF
+float func_20(float x, float y) {
+  return x + y;
+}
+// CHECK-LABEL: @func_20
+// STRICT: call float @llvm.experimental.constrained.fadd.f32(float {{.*}}, float {{.*}}, metadata !"round.tonearest", metadata !"fpexcept.strict")
+// DEFAULT: fadd float