Index: llvm/lib/Target/SystemZ/SystemZCallingConv.td
===================================================================
--- llvm/lib/Target/SystemZ/SystemZCallingConv.td
+++ llvm/lib/Target/SystemZ/SystemZCallingConv.td
@@ -221,9 +221,10 @@
   // XPLINK64 ABI compliant code widens integral types smaller than i64
   // to i64 before placing the parameters either on the stack or in registers.
   CCIfType<[i32], CCIfExtend<CCPromoteToType<i64>>>,
-  // Promote f32 to f64 and bitcast to i64, if it needs to be passed in GPRS.
-  CCIfType<[f32], CCIfNotFixed<CCPromoteToType<f64>>>,
-  CCIfType<[f64], CCIfNotFixed<CCBitConvertToType<i64>>>,
+  // Promote f32 to f64 and bitcast to i64, if it needs to be passed in GPRs.
+  // Although we assign the f32 vararg to be bitcast, it will first be promoted
+  // to an f64 within convertValVTToLocVT().
+  CCIfType<[f32, f64], CCIfNotFixed<CCBitConvertToType<i64>>>,
   // long double, can only be passed in GPR2 and GPR3, if available,
   // hence R2Q
   CCIfType<[f128], CCIfNotFixed<CCCustom<"CC_XPLINK64_Allocate128BitVararg">>>,
Index: llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
===================================================================
--- llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
+++ llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
@@ -1404,8 +1404,12 @@
     return DAG.getNode(ISD::ANY_EXTEND, DL, VA.getLocVT(), Value);
   case CCValAssign::BCvt: {
     assert(VA.getLocVT() == MVT::i64 || VA.getLocVT() == MVT::i128);
-    assert(VA.getValVT().isVector() || VA.getValVT() == MVT::f64 ||
-           VA.getValVT() == MVT::f128);
+    assert(VA.getValVT().isVector() || VA.getValVT() == MVT::f32 ||
+           VA.getValVT() == MVT::f64 || VA.getValVT() == MVT::f128);
+    // For an f32 vararg we need to first promote it to an f64 and then
+    // bitcast it to an i64.
+    if (VA.getValVT() == MVT::f32 && VA.getLocVT() == MVT::i64)
+      Value = DAG.getNode(ISD::FP_EXTEND, DL, MVT::f64, Value);
     MVT BitCastToType = VA.getValVT().isVector() && VA.getLocVT() == MVT::i64
                             ? MVT::v2i64
                             : VA.getLocVT();
Index: llvm/test/CodeGen/SystemZ/call-zos-vararg.ll
===================================================================
--- llvm/test/CodeGen/SystemZ/call-zos-vararg.ll
+++ llvm/test/CodeGen/SystemZ/call-zos-vararg.ll
@@ -189,6 +189,28 @@
   ret i64 %retval
 }
 
+; CHECK-LABEL: call_vararg_float0
+; CHECK:       lghi  1, 1
+; CHECK:       llihf 2, 1073692672
+define i64 @call_vararg_float0() {
+entry:
+  %retval = call i64 (i64, ...) @pass_vararg2(i64 1, float 1.953125)
+  ret i64 %retval
+}
+
+; CHECK-LABEL: call_vararg_float1
+; CHECK:       larl  1, @CPI17_0
+; CHECK:       le  0, 0(1)
+; CHECK:       llihf 0, 1073692672
+; CHECK:       llihh 2, 16384
+; CHECK:       llihh 3, 16392
+; CHECK:       stg  0, 2200(4)
+define i64 @call_vararg_float1() {
+entry:
+  %retval = call i64 (float, ...) @pass_vararg4(float 1.0, float 2.0, float 3.0, float 1.953125)
+  ret i64 %retval
+}
+
 ; Derived from C source:
 ; #define _VARARG_EXT_
 ; #include <stdarg.h>
@@ -227,3 +249,4 @@
 declare i64 @pass_vararg1(fp128 %arg0, ...)
 declare i64 @pass_vararg2(i64 %arg0, ...)
 declare i64 @pass_vararg3(...)
+declare i64 @pass_vararg4(float, ...)