diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
index 2db79228bf0e6..d4a2fe5e37ef5 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
@@ -1917,7 +1917,9 @@ Instruction *InstCombinerImpl::visitFPTrunc(FPTruncInst &FPT) {
       II->getOperandBundlesAsDefs(OpBundles);
       CallInst *NewCI =
           CallInst::Create(Overload, {InnerTrunc}, OpBundles, II->getName());
-      NewCI->copyFastMathFlags(II);
+      // A normal value may be converted to an infinity. It means that we cannot
+      // propagate ninf from the intrinsic. So we propagate FMF from fptrunc.
+      NewCI->copyFastMathFlags(&FPT);
       return NewCI;
     }
     }
diff --git a/llvm/test/Transforms/InstCombine/double-float-shrink-2.ll b/llvm/test/Transforms/InstCombine/double-float-shrink-2.ll
index f2049e2813ebc..f884d2bd1ab5b 100644
--- a/llvm/test/Transforms/InstCombine/double-float-shrink-2.ll
+++ b/llvm/test/Transforms/InstCombine/double-float-shrink-2.ll
@@ -449,7 +449,7 @@ define float @test_shrink_intrin_fabs_fast_double_src(double %D) {
 ; CHECK-NEXT:    ret float [[F]]
 ;
   %E = call fast double @llvm.fabs.f64(double %D)
-  %F = fptrunc double %E to float
+  %F = fptrunc fast double %E to float
   ret float %F
 }
 
@@ -611,7 +611,7 @@ define half @test_mismatched_type_intrin_fabs_fast_double_src(double %D) {
 ; CHECK-NEXT:    ret half [[F]]
 ;
   %E = call fast double @llvm.fabs.f64(double %D)
-  %F = fptrunc double %E to half
+  %F = fptrunc fast double %E to half
   ret half %F
 }
 
diff --git a/llvm/test/Transforms/InstCombine/fabs.ll b/llvm/test/Transforms/InstCombine/fabs.ll
index 0a22d1431b5f1..0d9374410a1d8 100644
--- a/llvm/test/Transforms/InstCombine/fabs.ll
+++ b/llvm/test/Transforms/InstCombine/fabs.ll
@@ -1522,7 +1522,7 @@ define float @test_fabs_nsz_used_by_frem(float %x) {
 define half @test_fabs_nsz_used_by_fptrunc(float %x) {
 ; CHECK-LABEL: @test_fabs_nsz_used_by_fptrunc(
 ; CHECK-NEXT:    [[TMP1:%.*]] = fptrunc float [[X:%.*]] to half
-; CHECK-NEXT:    [[OP:%.*]] = call nsz half @llvm.fabs.f16(half [[TMP1]])
+; CHECK-NEXT:    [[OP:%.*]] = call half @llvm.fabs.f16(half [[TMP1]])
 ; CHECK-NEXT:    ret half [[OP]]
 ;
   %cmp = fcmp oge float %x, 0.000000e+00
diff --git a/llvm/test/Transforms/InstCombine/fpcast.ll b/llvm/test/Transforms/InstCombine/fpcast.ll
index d5290b572aefd..1a3faceebf244 100644
--- a/llvm/test/Transforms/InstCombine/fpcast.ll
+++ b/llvm/test/Transforms/InstCombine/fpcast.ll
@@ -32,7 +32,7 @@ define half @test3(float %a) {
 define half @test3_fast(float %a) {
 ; CHECK-LABEL: @test3_fast(
 ; CHECK-NEXT:    [[TMP1:%.*]] = fptrunc float [[A:%.*]] to half
-; CHECK-NEXT:    [[C:%.*]] = call half @llvm.fabs.f16(half [[TMP1]])
+; CHECK-NEXT:    [[C:%.*]] = call fast half @llvm.fabs.f16(half [[TMP1]])
 ; CHECK-NEXT:    ret half [[C]]
 ;
   %b = call float @llvm.fabs.f32(float %a)
@@ -40,6 +40,39 @@ define half @test3_fast(float %a) {
   ret half %c
 }
 
+define half @test3_both_ninf(float %a) {
+; CHECK-LABEL: @test3_both_ninf(
+; CHECK-NEXT:    [[TMP1:%.*]] = fptrunc float [[A:%.*]] to half
+; CHECK-NEXT:    [[C:%.*]] = call ninf half @llvm.fabs.f16(half [[TMP1]])
+; CHECK-NEXT:    ret half [[C]]
+;
+  %b = call ninf float @llvm.fabs.f32(float %a)
+  %c = fptrunc ninf float %b to half
+  ret half %c
+}
+
+define half @test3_fabs_ninf(float %a) {
+; CHECK-LABEL: @test3_fabs_ninf(
+; CHECK-NEXT:    [[TMP1:%.*]] = fptrunc float [[A:%.*]] to half
+; CHECK-NEXT:    [[C:%.*]] = call half @llvm.fabs.f16(half [[TMP1]])
+; CHECK-NEXT:    ret half [[C]]
+;
+  %b = call ninf float @llvm.fabs.f32(float %a)
+  %c = fptrunc float %b to half
+  ret half %c
+}
+
+define half @test3_fptrunc_ninf(float %a) {
+; CHECK-LABEL: @test3_fptrunc_ninf(
+; CHECK-NEXT:    [[TMP1:%.*]] = fptrunc float [[A:%.*]] to half
+; CHECK-NEXT:    [[C:%.*]] = call ninf half @llvm.fabs.f16(half [[TMP1]])
+; CHECK-NEXT:    ret half [[C]]
+;
+  %b = call float @llvm.fabs.f32(float %a)
+  %c = fptrunc ninf float %b to half
+  ret half %c
+}
+
 define half @fneg_fptrunc(float %a) {
 ; CHECK-LABEL: @fneg_fptrunc(
 ; CHECK-NEXT:    [[TMP1:%.*]] = fptrunc float [[A:%.*]] to half