[llvm] ea0676f - [SystemZ][z/OS] Fix f32 variadic argument assertion

[Neumann Hon via llvm-commits]

Author: Mubariz Afzal
Date: 2022-02-15T18:11:57-05:00
New Revision: ea0676f97d734196b15da7553cd407e6a36cef2d

URL: https://github.com/llvm/llvm-project/commit/ea0676f97d734196b15da7553cd407e6a36cef2d
DIFF: https://github.com/llvm/llvm-project/commit/ea0676f97d734196b15da7553cd407e6a36cef2d.diff

LOG: [SystemZ][z/OS] Fix f32 variadic argument assertion

The tablegen lines that specify the XPLINK64 calling convention for promoting an f32 vararg to an f64 are effectively overwritten by the following tablegen line which bitcast an f64 vararg to an i64 (so that it can be used in the GPRs). It becomes a bitcast from f32 to i64.

Since we don't handle a bitcast for f32s this caused an assertion.

Added: 
    

Modified: 
    llvm/lib/Target/SystemZ/SystemZCallingConv.td
    llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
    llvm/test/CodeGen/SystemZ/call-zos-vararg.ll

Removed: 
    


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diff  --git a/llvm/lib/Target/SystemZ/SystemZCallingConv.td b/llvm/lib/Target/SystemZ/SystemZCallingConv.td
index a7ea5e1e4bf8..bc5f6a15d493 100644
--- a/llvm/lib/Target/SystemZ/SystemZCallingConv.td
+++ b/llvm/lib/Target/SystemZ/SystemZCallingConv.td
@@ -225,9 +225,10 @@ def CC_SystemZ_XPLINK64 : CallingConv<[
   // 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">>>,

diff  --git a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
index 0eded62347be..c125ceed3fcb 100644
--- a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
@@ -1358,8 +1358,12 @@ static SDValue convertValVTToLocVT(SelectionDAG &DAG, const SDLoc &DL,
     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();

diff  --git a/llvm/test/CodeGen/SystemZ/call-zos-vararg.ll b/llvm/test/CodeGen/SystemZ/call-zos-vararg.ll
index 2efe27172efc..8e4974c36cad 100644
--- a/llvm/test/CodeGen/SystemZ/call-zos-vararg.ll
+++ b/llvm/test/CodeGen/SystemZ/call-zos-vararg.ll
@@ -189,7 +189,30 @@ entry:
   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:       llihf 0, 1073692672
+; CHECK-NEXT:  stg  0, 2200(4)
+; CHECK:       larl  1, @CPI21_0
+; CHECK-NEXT:  le  0, 0(1)
+; CHECK:       llihh 2, 16384
+; CHECK:       llihh 3, 16392
+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
+}
+
 declare i64 @pass_vararg0(i64 %arg0, i64 %arg1, ...)
 declare i64 @pass_vararg1(fp128 %arg0, ...)
 declare i64 @pass_vararg2(i64 %arg0, ...)
 declare i64 @pass_vararg3(...)
+declare i64 @pass_vararg4(float, ...)