Index: include/llvm/Analysis/TargetLibraryInfo.def
===================================================================
--- include/llvm/Analysis/TargetLibraryInfo.def
+++ include/llvm/Analysis/TargetLibraryInfo.def
@@ -372,6 +372,15 @@
 /// float __sinpif(float x);
 TLI_DEFINE_ENUM_INTERNAL(sinpif)
 TLI_DEFINE_STRING_INTERNAL("__sinpif")
+/// int __small_fprintf(FILE *stream, const char *format, ...);
+TLI_DEFINE_ENUM_INTERNAL(small_fprintf)
+TLI_DEFINE_STRING_INTERNAL("__small_fprintf")
+/// int __small_printf(const char *format, ...);
+TLI_DEFINE_ENUM_INTERNAL(small_printf)
+TLI_DEFINE_STRING_INTERNAL("__small_printf")
+/// int __small_sprintf(char *str, const char *format, ...);
+TLI_DEFINE_ENUM_INTERNAL(small_sprintf)
+TLI_DEFINE_STRING_INTERNAL("__small_sprintf")
 /// double __sqrt_finite(double x);
 TLI_DEFINE_ENUM_INTERNAL(sqrt_finite)
 TLI_DEFINE_STRING_INTERNAL("__sqrt_finite")
Index: lib/Analysis/TargetLibraryInfo.cpp
===================================================================
--- lib/Analysis/TargetLibraryInfo.cpp
+++ lib/Analysis/TargetLibraryInfo.cpp
@@ -152,13 +152,21 @@
     TLI.setAvailableWithName(LibFunc_fputs, "fputs$UNIX2003");
   }
 
-  // iprintf and friends are only available on XCore and TCE.
-  if (T.getArch() != Triple::xcore && T.getArch() != Triple::tce) {
+  // iprintf and friends are only available on XCore, TCE, and WASI.
+  if (T.getArch() != Triple::xcore && T.getArch() != Triple::tce &&
+      T.getOS() != Triple::WASI) {
     TLI.setUnavailable(LibFunc_iprintf);
     TLI.setUnavailable(LibFunc_siprintf);
     TLI.setUnavailable(LibFunc_fiprintf);
   }
 
+  // __small_printf and friends are only available on WASI.
+  if (T.getOS() != Triple::WASI) {
+    TLI.setUnavailable(LibFunc_small_printf);
+    TLI.setUnavailable(LibFunc_small_sprintf);
+    TLI.setUnavailable(LibFunc_small_fprintf);
+  }
+
   if (T.isOSWindows() && !T.isOSCygMing()) {
     // Win32 does not support long double
     TLI.setUnavailable(LibFunc_acosl);
@@ -738,6 +746,7 @@
   case LibFunc_stat:
   case LibFunc_statvfs:
   case LibFunc_siprintf:
+  case LibFunc_small_sprintf:
   case LibFunc_sprintf:
     return (NumParams >= 2 && FTy.getParamType(0)->isPointerTy() &&
             FTy.getParamType(1)->isPointerTy() &&
@@ -835,6 +844,7 @@
   case LibFunc_getenv:
   case LibFunc_getpwnam:
   case LibFunc_iprintf:
+  case LibFunc_small_printf:
   case LibFunc_pclose:
   case LibFunc_perror:
   case LibFunc_printf:
@@ -914,6 +924,7 @@
             FTy.getParamType(1)->isPointerTy());
   case LibFunc_fscanf:
   case LibFunc_fiprintf:
+  case LibFunc_small_fprintf:
   case LibFunc_fprintf:
     return (NumParams >= 2 && FTy.getReturnType()->isIntegerTy() &&
             FTy.getParamType(0)->isPointerTy() &&
Index: lib/Transforms/Utils/SimplifyLibCalls.cpp
===================================================================
--- lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -104,6 +104,12 @@
   });
 }
 
+static bool callHasFP128Argument(const CallInst *CI) {
+  return any_of(CI->operands(), [](const Use &OI) {
+    return OI->getType()->isFP128Ty();
+  });
+}
+
 static Value *convertStrToNumber(CallInst *CI, StringRef &Str, int64_t Base) {
   if (Base < 2 || Base > 36)
     // handle special zero base
@@ -2031,6 +2037,20 @@
     B.Insert(New);
     return New;
   }
+
+  // printf(format, ...) -> __small_printf(format, ...) if no 128-bit floating point
+  // arguments.
+  if (TLI->has(LibFunc_small_printf) && !callHasFP128Argument(CI)) {
+    Module *M = B.GetInsertBlock()->getParent()->getParent();
+    auto SmallPrintFFn =
+        M->getOrInsertFunction(TLI->getName(LibFunc_small_printf),
+                               FT, Callee->getAttributes());
+    CallInst *New = cast<CallInst>(CI->clone());
+    New->setCalledFunction(SmallPrintFFn);
+    B.Insert(New);
+    return New;
+  }
+
   return nullptr;
 }
 
@@ -2110,6 +2130,20 @@
     B.Insert(New);
     return New;
   }
+
+  // sprintf(str, format, ...) -> __small_sprintf(str, format, ...) if no 128-bit
+  // floating point arguments.
+  if (TLI->has(LibFunc_small_sprintf) && !callHasFP128Argument(CI)) {
+    Module *M = B.GetInsertBlock()->getParent()->getParent();
+    auto SmallSPrintFFn =
+        M->getOrInsertFunction(TLI->getName(LibFunc_small_sprintf),
+                               FT, Callee->getAttributes());
+    CallInst *New = cast<CallInst>(CI->clone());
+    New->setCalledFunction(SmallSPrintFFn);
+    B.Insert(New);
+    return New;
+  }
+
   return nullptr;
 }
 
@@ -2267,6 +2301,20 @@
     B.Insert(New);
     return New;
   }
+
+  // fprintf(stream, format, ...) -> __small_fprintf(stream, format, ...) if no
+  // 128-bit floating point arguments.
+  if (TLI->has(LibFunc_small_fprintf) && !callHasFP128Argument(CI)) {
+    Module *M = B.GetInsertBlock()->getParent()->getParent();
+    auto SmallFPrintFFn =
+        M->getOrInsertFunction(TLI->getName(LibFunc_small_fprintf),
+                               FT, Callee->getAttributes());
+    CallInst *New = cast<CallInst>(CI->clone());
+    New->setCalledFunction(SmallFPrintFFn);
+    B.Insert(New);
+    return New;
+  }
+
   return nullptr;
 }
 
Index: test/Transforms/InstCombine/fprintf-1.ll
===================================================================
--- test/Transforms/InstCombine/fprintf-1.ll
+++ test/Transforms/InstCombine/fprintf-1.ll
@@ -2,6 +2,7 @@
 ;
 ; RUN: opt < %s -instcombine -S | FileCheck %s
 ; RUN: opt < %s -mtriple xcore-xmos-elf -instcombine -S | FileCheck %s -check-prefix=CHECK-IPRINTF
+; RUN: opt < %s -mtriple wasm32-unknown-wasi -instcombine -S | FileCheck %s -check-prefix=CHECK-SMALL-PRINTF
 
 target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
 
@@ -11,6 +12,7 @@
 @percent_c = constant [3 x i8] c"%c\00"
 @percent_d = constant [3 x i8] c"%d\00"
 @percent_f = constant [3 x i8] c"%f\00"
+@percent_Lf = constant [4 x i8] c"%Lf\00"
 @percent_s = constant [3 x i8] c"%s\00"
 
 declare i32 @fprintf(%FILE*, i8*, ...)
@@ -61,6 +63,17 @@
 ; CHECK-IPRINTF-NEXT: ret void
 }
 
+; Check fprintf(fp, fmt, ...) -> __small_fprintf(fp, fmt, ...) if no fp128.
+
+define void @test_simplify6(%FILE* %fp) {
+; CHECK-SMALL-PRINTF-LABEL: @test_simplify6(
+  %fmt = getelementptr [3 x i8], [3 x i8]* @percent_f, i32 0, i32 0
+  call i32 (%FILE*, i8*, ...) @fprintf(%FILE* %fp, i8* %fmt, double 1.87)
+; CHECK-SMALL-PRINTF-NEXT: call i32 (%FILE*, i8*, ...) @__small_fprintf(%FILE* %fp, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @percent_f, i32 0, i32 0), double 1.870000e+00)
+  ret void
+; CHECK-SMALL-PRINTF-NEXT: ret void
+}
+
 define void @test_simplify5(%FILE* %fp) {
 ; CHECK-LABEL: @test_simplify5(
   %fmt = getelementptr [13 x i8], [13 x i8]* @hello_world, i32 0, i32 0
@@ -96,3 +109,12 @@
   ret i32 %1
 ; CHECK-NEXT: ret i32 %1
 }
+
+define void @test_no_simplify4(%FILE* %fp) {
+; CHECK-SMALL-PRINTF-LABEL: @test_no_simplify4(
+  %fmt = getelementptr [4 x i8], [4 x i8]* @percent_Lf, i32 0, i32 0
+  call i32 (%FILE*, i8*, ...) @fprintf(%FILE* %fp, i8* %fmt, fp128 0xLC0000000000000003FFFDEB851EB851E)
+; CHECK-SMALL-PRINTF-NEXT: call i32 (%FILE*, i8*, ...) @fprintf(%FILE* %fp, i8* getelementptr inbounds ([4 x i8], [4 x i8]* @percent_Lf, i32 0, i32 0), fp128 0xLC0000000000000003FFFDEB851EB851E)
+  ret void
+; CHECK-SMALL-PRINTF-NEXT: ret void
+}
Index: test/Transforms/InstCombine/printf-1.ll
===================================================================
--- test/Transforms/InstCombine/printf-1.ll
+++ test/Transforms/InstCombine/printf-1.ll
@@ -2,6 +2,7 @@
 ;
 ; RUN: opt < %s -instcombine -S | FileCheck %s
 ; RUN: opt < %s -mtriple xcore-xmos-elf -instcombine -S | FileCheck %s -check-prefix=CHECK-IPRINTF
+; RUN: opt < %s -mtriple wasm32-unknown-wasi -instcombine -S | FileCheck %s -check-prefix=CHECK-SMALL-PRINTF
 
 target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
 
@@ -12,6 +13,7 @@
 @percent_c = constant [3 x i8] c"%c\00"
 @percent_d = constant [3 x i8] c"%d\00"
 @percent_f = constant [3 x i8] c"%f\00"
+@percent_Lf = constant [4 x i8] c"%Lf\00"
 @percent_s = constant [4 x i8] c"%s\0A\00"
 @empty = constant [1 x i8] c"\00"
 ; CHECK: [[$STR:@[a-z0-9]+]] = private unnamed_addr constant [12 x i8] c"hello world\00", align 1
@@ -104,6 +106,17 @@
 ; CHECK-IPRINTF-NEXT: ret void
 }
 
+; Check printf(format, ...) -> __small_printf(format, ...) if no fp128.
+
+define void @test_simplify8() {
+; CHECK-SMALL-PRINTF-LABEL: @test_simplify8(
+  %fmt = getelementptr [3 x i8], [3 x i8]* @percent_f, i32 0, i32 0
+  call i32 (i8*, ...) @printf(i8* %fmt, double 1.87)
+; CHECK-SMALL-PRINTF-NEXT: call i32 (i8*, ...) @__small_printf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @percent_f, i32 0, i32 0), double 1.870000e+00)
+  ret void
+; CHECK-SMALL-PRINTF-NEXT: ret void
+}
+
 define void @test_no_simplify1() {
 ; CHECK-IPRINTF-LABEL: @test_no_simplify1(
   %fmt = getelementptr [3 x i8], [3 x i8]* @percent_f, i32 0, i32 0
@@ -129,3 +142,12 @@
   ret i32 %ret
 ; CHECK-NEXT: ret i32 %ret
 }
+
+define void @test_no_simplify4() {
+; CHECK-SMALL-PRINTF-LABEL: @test_no_simplify4(
+  %fmt = getelementptr [4 x i8], [4 x i8]* @percent_Lf, i32 0, i32 0
+  call i32 (i8*, ...) @printf(i8* %fmt, fp128 0xLC0000000000000003FFFDEB851EB851E)
+; CHECK-SMALL-PRINTF-NEXT: call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @percent_Lf, i32 0, i32 0), fp128 0xLC0000000000000003FFFDEB851EB851E)
+  ret void
+; CHECK-SMALL-PRINTF-NEXT: ret void
+}
Index: test/Transforms/InstCombine/sprintf-1.ll
===================================================================
--- test/Transforms/InstCombine/sprintf-1.ll
+++ test/Transforms/InstCombine/sprintf-1.ll
@@ -2,6 +2,7 @@
 ;
 ; RUN: opt < %s -instcombine -S | FileCheck %s
 ; RUN: opt < %s -mtriple xcore-xmos-elf -instcombine -S | FileCheck %s -check-prefix=CHECK-IPRINTF
+; RUN: opt < %s -mtriple wasm32-unknown-wasi -instcombine -S | FileCheck %s -check-prefix=CHECK-SMALL-PRINTF
 
 target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
 
@@ -12,6 +13,7 @@
 @percent_c = constant [3 x i8] c"%c\00"
 @percent_d = constant [3 x i8] c"%d\00"
 @percent_f = constant [3 x i8] c"%f\00"
+@percent_Lf = constant [4 x i8] c"%Lf\00"
 @percent_s = constant [3 x i8] c"%s\00"
 
 declare i32 @sprintf(i8*, i8*, ...)
@@ -82,6 +84,17 @@
 ; CHECK-IPRINTF-NEXT: ret void
 }
 
+; Check sprintf(dst, format, ...) -> __small_sprintf(str, format, ...) if no fp128.
+
+define void @test_simplify7(i8* %dst) {
+; CHECK-SMALL-PRINTF-LABEL: @test_simplify7(
+  %fmt = getelementptr [3 x i8], [3 x i8]* @percent_f, i32 0, i32 0
+  call i32 (i8*, i8*, ...) @sprintf(i8* %dst, i8* %fmt, double 1.87)
+; CHECK-SMALL-PRINTF-NEXT: call i32 (i8*, i8*, ...) @__small_sprintf(i8* %dst, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @percent_f, i32 0, i32 0), double 1.870000e+00)
+  ret void
+; CHECK-SMALL-PRINTF-NEXT: ret void
+}
+
 define void @test_no_simplify1(i8* %dst) {
 ; CHECK-IPRINTF-LABEL: @test_no_simplify1(
   %fmt = getelementptr [3 x i8], [3 x i8]* @percent_f, i32 0, i32 0
@@ -98,3 +111,12 @@
   ret void
 ; CHECK-NEXT: ret void
 }
+
+define void @test_no_simplify3(i8* %dst) {
+; CHECK-SMALL-PRINTF-LABEL: @test_no_simplify3(
+  %fmt = getelementptr [4 x i8], [4 x i8]* @percent_Lf, i32 0, i32 0
+  call i32 (i8*, i8*, ...) @sprintf(i8* %dst, i8* %fmt, fp128 0xLC0000000000000003FFFDEB851EB851E)
+; CHECK-SMALL-PRINTF-NEXT: call i32 (i8*, i8*, ...) @sprintf(i8* %dst, i8* getelementptr inbounds ([4 x i8], [4 x i8]* @percent_Lf, i32 0, i32 0), fp128 0xLC0000000000000003FFFDEB851EB851E)
+  ret void
+; CHECK-SMALL-PRINTF-NEXT: ret void
+}
Index: unittests/Analysis/TargetLibraryInfoTest.cpp
===================================================================
--- unittests/Analysis/TargetLibraryInfoTest.cpp
+++ unittests/Analysis/TargetLibraryInfoTest.cpp
@@ -493,6 +493,9 @@
       "declare i32 @fiprintf(%struct*, i8*, ...)\n"
       "declare i32 @iprintf(i8*, ...)\n"
       "declare i32 @siprintf(i8*, i8*, ...)\n"
+      "declare i32 @__small_fprintf(%struct*, i8*, ...)\n"
+      "declare i32 @__small_printf(i8*, ...)\n"
+      "declare i32 @__small_sprintf(i8*, i8*, ...)\n"
 
       "declare i32 @htonl(i32)\n"
       "declare i16 @htons(i16)\n"