diff --git a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
--- a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
+++ b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
@@ -1624,6 +1624,7 @@
     // its calls will be.
     auto localBuilder =
         std::make_unique<fir::FirOpBuilder>(function, builder.getKindMap());
+    localBuilder->setFastMathFlags(builder.getFastMathFlags());
     localBuilder->setInsertionPointToStart(&function.front());
     // Location of code inside wrapper of the wrapper is independent from
     // the location of the intrinsic call.
diff --git a/flang/test/Lower/Intrinsics/exp.f90 b/flang/test/Lower/Intrinsics/exp.f90
--- a/flang/test/Lower/Intrinsics/exp.f90
+++ b/flang/test/Lower/Intrinsics/exp.f90
@@ -47,12 +47,12 @@
 
 ! CHECK-LABEL: private @fir.exp.f32.f32
 ! CHECK-SAME: (%[[ARG32_OUTLINE:.*]]: f32) -> f32
-! CHECK: %[[RESULT32_OUTLINE:.*]] = math.exp %[[ARG32_OUTLINE]] : f32
+! CHECK: %[[RESULT32_OUTLINE:.*]] = math.exp %[[ARG32_OUTLINE]] fastmath<contract> : f32
 ! CHECK: return %[[RESULT32_OUTLINE]] : f32
 
 ! CHECK-LABEL: private @fir.exp.f64.f64
 ! CHECK-SAME: (%[[ARG64_OUTLINE:.*]]: f64) -> f64
-! CHECK: %[[RESULT64_OUTLINE:.*]] = math.exp %[[ARG64_OUTLINE]] : f64
+! CHECK: %[[RESULT64_OUTLINE:.*]] = math.exp %[[ARG64_OUTLINE]] fastmath<contract> : f64
 ! CHECK: return %[[RESULT64_OUTLINE]] : f64
 
 ! CMPLX-LABEL: private @fir.exp.z4.z4
@@ -60,7 +60,7 @@
 ! CMPLX-FAST: %[[C:.*]] = fir.convert %[[ARG32_OUTLINE]] : (!fir.complex<4>) -> complex<f32>
 ! CMPLX-FAST: %[[E:.*]] = complex.exp %[[C]] : complex<f32>
 ! CMPLX-FAST: %[[RESULT32_OUTLINE:.*]] = fir.convert %[[E]] : (complex<f32>) -> !fir.complex<4>
-! CMPLX-PRECISE: %[[RESULT32_OUTLINE:.*]] = fir.call @cexpf(%[[ARG32_OUTLINE]]) : (!fir.complex<4>) -> !fir.complex<4>
+! CMPLX-PRECISE: %[[RESULT32_OUTLINE:.*]] = fir.call @cexpf(%[[ARG32_OUTLINE]]) fastmath<contract> : (!fir.complex<4>) -> !fir.complex<4>
 ! CMPLX: return %[[RESULT32_OUTLINE]] : !fir.complex<4>
 
 ! CMPLX-LABEL: private @fir.exp.z8.z8
@@ -68,5 +68,5 @@
 ! CMPLX-FAST: %[[C:.*]] = fir.convert %[[ARG64_OUTLINE]] : (!fir.complex<8>) -> complex<f64>
 ! CMPLX-FAST: %[[E:.*]] = complex.exp %[[C]] : complex<f64>
 ! CMPLX-FAST: %[[RESULT64_OUTLINE:.*]] = fir.convert %[[E]] : (complex<f64>) -> !fir.complex<8>
-! CMPLX-PRECISE: %[[RESULT64_OUTLINE:.*]] = fir.call @cexp(%[[ARG64_OUTLINE]]) : (!fir.complex<8>) -> !fir.complex<8>
+! CMPLX-PRECISE: %[[RESULT64_OUTLINE:.*]] = fir.call @cexp(%[[ARG64_OUTLINE]]) fastmath<contract> : (!fir.complex<8>) -> !fir.complex<8>
 ! CMPLX: return %[[RESULT64_OUTLINE]] : !fir.complex<8>
diff --git a/flang/test/Lower/Intrinsics/log.f90 b/flang/test/Lower/Intrinsics/log.f90
--- a/flang/test/Lower/Intrinsics/log.f90
+++ b/flang/test/Lower/Intrinsics/log.f90
@@ -67,12 +67,12 @@
 
 ! CHECK-LABEL: private @fir.log.f32.f32
 ! CHECK-SAME: (%[[ARG32_OUTLINE:.*]]: f32) -> f32
-! CHECK: %[[RESULT32_OUTLINE:.*]] = math.log %[[ARG32_OUTLINE]] : f32
+! CHECK: %[[RESULT32_OUTLINE:.*]] = math.log %[[ARG32_OUTLINE]] fastmath<contract> : f32
 ! CHECK: return %[[RESULT32_OUTLINE]] : f32
 
 ! CHECK-LABEL: private @fir.log.f64.f64
 ! CHECK-SAME: (%[[ARG64_OUTLINE:.*]]: f64) -> f64
-! CHECK: %[[RESULT64_OUTLINE:.*]] = math.log %[[ARG64_OUTLINE]] : f64
+! CHECK: %[[RESULT64_OUTLINE:.*]] = math.log %[[ARG64_OUTLINE]] fastmath<contract> : f64
 ! CHECK: return %[[RESULT64_OUTLINE]] : f64
 
 ! CMPLX-LABEL: private @fir.log.z4.z4
@@ -80,7 +80,7 @@
 ! CMPLX-FAST: %[[C:.*]] = fir.convert %[[ARG32_OUTLINE]] : (!fir.complex<4>) -> complex<f32>
 ! CMPLX-FAST: %[[E:.*]] = complex.log %[[C]] : complex<f32>
 ! CMPLX-FAST: %[[RESULT32_OUTLINE:.*]] = fir.convert %[[E]] : (complex<f32>) -> !fir.complex<4>
-! CMPLX-PRECISE: %[[RESULT32_OUTLINE:.*]] = fir.call @clogf(%[[ARG32_OUTLINE]]) : (!fir.complex<4>) -> !fir.complex<4>
+! CMPLX-PRECISE: %[[RESULT32_OUTLINE:.*]] = fir.call @clogf(%[[ARG32_OUTLINE]]) fastmath<contract> : (!fir.complex<4>) -> !fir.complex<4>
 ! CMPLX: return %[[RESULT32_OUTLINE]] : !fir.complex<4>
 
 ! CMPLX-LABEL: private @fir.log.z8.z8
@@ -88,15 +88,15 @@
 ! CMPLX-FAST: %[[C:.*]] = fir.convert %[[ARG64_OUTLINE]] : (!fir.complex<8>) -> complex<f64>
 ! CMPLX-FAST: %[[E:.*]] = complex.log %[[C]] : complex<f64>
 ! CMPLX-FAST: %[[RESULT64_OUTLINE:.*]] = fir.convert %[[E]] : (complex<f64>) -> !fir.complex<8>
-! CMPLX-PRECISE: %[[RESULT64_OUTLINE:.*]] = fir.call @clog(%[[ARG64_OUTLINE]]) : (!fir.complex<8>) -> !fir.complex<8>
+! CMPLX-PRECISE: %[[RESULT64_OUTLINE:.*]] = fir.call @clog(%[[ARG64_OUTLINE]]) fastmath<contract> : (!fir.complex<8>) -> !fir.complex<8>
 ! CMPLX: return %[[RESULT64_OUTLINE]] : !fir.complex<8>
 
 ! CHECK-LABEL: private @fir.log10.f32.f32
 ! CHECK-SAME: (%[[ARG32_OUTLINE:.*]]: f32) -> f32
-! CHECK: %[[RESULT32_OUTLINE:.*]] = math.log10 %[[ARG32_OUTLINE]] : f32
+! CHECK: %[[RESULT32_OUTLINE:.*]] = math.log10 %[[ARG32_OUTLINE]] fastmath<contract> : f32
 ! CHECK: return %[[RESULT32_OUTLINE]] : f32
 
 ! CHECK-LABEL: private @fir.log10.f64.f64
 ! CHECK-SAME: (%[[ARG64_OUTLINE:.*]]: f64) -> f64
-! CHECK: %[[RESULT64_OUTLINE:.*]] = math.log10 %[[ARG64_OUTLINE]] : f64
+! CHECK: %[[RESULT64_OUTLINE:.*]] = math.log10 %[[ARG64_OUTLINE]] fastmath<contract> : f64
 ! CHECK: return %[[RESULT64_OUTLINE]] : f64
diff --git a/flang/test/Lower/Intrinsics/math-runtime-options.f90 b/flang/test/Lower/Intrinsics/math-runtime-options.f90
--- a/flang/test/Lower/Intrinsics/math-runtime-options.f90
+++ b/flang/test/Lower/Intrinsics/math-runtime-options.f90
@@ -20,10 +20,10 @@
 end subroutine
 
 ! FIR: @fir.cos.f32.f32(%arg0: f32) -> f32 attributes
-! FAST: math.cos %arg0 : f32
-! RELAXED: math.cos %arg0 : f32
-! PRECISE: fir.call @cosf(%arg0) : (f32) -> f32
+! FAST: math.cos %arg0 fastmath<contract> : f32
+! RELAXED: math.cos %arg0 fastmath<contract> : f32
+! PRECISE: fir.call @cosf(%arg0) fastmath<contract> : (f32) -> f32
 ! FIR: @fir.cos.f64.f64(%arg0: f64) -> f64
-! FAST: math.cos %arg0 : f64
-! RELAXED: math.cos %arg0 : f64
-! PRECISE: fir.call @cos(%arg0) : (f64) -> f64
+! FAST: math.cos %arg0 fastmath<contract> : f64
+! RELAXED: math.cos %arg0 fastmath<contract> : f64
+! PRECISE: fir.call @cos(%arg0) fastmath<contract> : (f64) -> f64
diff --git a/flang/test/Lower/dummy-procedure.f90 b/flang/test/Lower/dummy-procedure.f90
--- a/flang/test/Lower/dummy-procedure.f90
+++ b/flang/test/Lower/dummy-procedure.f90
@@ -154,14 +154,14 @@
 
 ! CHECK-LABEL: func private @fir.acos.f32.ref_f32(%arg0: !fir.ref<f32>) -> f32
   !CHECK: %[[load:.*]] = fir.load %arg0
-  !CHECK: %[[res:.*]] = fir.call @acosf(%[[load]]) : (f32) -> f32
+  !CHECK: %[[res:.*]] = fir.call @acosf(%[[load]]) fastmath<contract> : (f32) -> f32
   !CHECK: return %[[res]] : f32
 
 ! CHECK-LABEL: func private @fir.atan2.f32.ref_f32.ref_f32(
 ! CHECK-SAME: %[[x:.*]]: !fir.ref<f32>, %[[y:.*]]: !fir.ref<f32>) -> f32
   ! CHECK-DAG: %[[xload:.*]] = fir.load %[[x]] : !fir.ref<f32>
   ! CHECK-DAG: %[[yload:.*]] = fir.load %[[y]] : !fir.ref<f32>
-  ! CHECK: %[[atan2:.*]] = math.atan2 %[[xload]], %[[yload]] : f32
+  ! CHECK: %[[atan2:.*]] = math.atan2 %[[xload]], %[[yload]] fastmath<contract> : f32
   ! CHECK: return %[[atan2]] : f32
 
 !CHECK-LABEL: func private @fir.aimag.f32.ref_z4(%arg0: !fir.ref<!fir.complex<4>>)