maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[InstCombine] Simplify calls with casted `returned` attribute 

The handling of the `returned` attribute in D75815 did miss the case
where the argument is (bit)casted to a different type. This is
explicitly allowed by the language reference and exposed by the
Attributor.

Reviewed By: lebedev.ri

Differential Revision: https://reviews.llvm.org/D77977
This commit is contained in:
Johannes Doerfert 2020-04-12 12:41:56 -05:00
parent 8ad19ffa7b
commit ea7f17ee38
2 changed files with 50 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
View File

@ -4654,8 +4654,13 @@ Instruction *InstCombiner::visitCallBase(CallBase &Call) {
}
if (!Call.use_empty() && !Call.isMustTailCall())
if (Value *ReturnedArg = Call.getReturnedArgOperand())
return replaceInstUsesWith(Call, ReturnedArg);
if (Value *ReturnedArg = Call.getReturnedArgOperand()) {
Type *CallTy = Call.getType();
Type *RetArgTy = ReturnedArg->getType();
if (RetArgTy->canLosslesslyBitCastTo(CallTy))
return replaceInstUsesWith(
Call, Builder.CreateBitOrPointerCast(ReturnedArg, CallTy));
}
if (isAllocLikeFn(&Call, &TLI))
return visitAllocSite(Call);

43
llvm/test/Transforms/InstCombine/call-returned.ll
View File

@ -3,6 +3,8 @@
declare i32 @passthru_i32(i32 returned)
declare i8* @passthru_p8(i8* returned)
declare i8* @passthru_p8_from_p32(i32* returned)
declare <8 x i8> @passthru_8i8v_from_2i32v(<2 x i32> returned)
define i32 @returned_const_int_arg() {
; CHECK-LABEL: @returned_const_int_arg(
@ -22,6 +24,46 @@ define i8* @returned_const_ptr_arg() {
ret i8* %x
}
define i8* @returned_const_ptr_arg_casted() {
; CHECK-LABEL: @returned_const_ptr_arg_casted(
; CHECK-NEXT: [[X:%.*]] = call i8* @passthru_p8_from_p32(i32* null)
; CHECK-NEXT: ret i8* null
;
%x = call i8* @passthru_p8_from_p32(i32* null)
ret i8* %x
}
define i8* @returned_ptr_arg_casted(i32* %a) {
; CHECK-LABEL: @returned_ptr_arg_casted(
; CHECK-NEXT: [[TMP1:%.*]] = bitcast i32* [[A:%.*]] to i8*
; CHECK-NEXT: [[X:%.*]] = call i8* @passthru_p8_from_p32(i32* [[A]])
; CHECK-NEXT: ret i8* [[TMP1]]
;
%x = call i8* @passthru_p8_from_p32(i32* %a)
ret i8* %x
}
@GV = constant <2 x i32> zeroinitializer
define <8 x i8> @returned_const_vec_arg_casted() {
; CHECK-LABEL: @returned_const_vec_arg_casted(
; CHECK-NEXT: [[X:%.*]] = call <8 x i8> @passthru_8i8v_from_2i32v(<2 x i32> zeroinitializer)
; CHECK-NEXT: ret <8 x i8> zeroinitializer
;
%v = load <2 x i32>, <2 x i32>* @GV
%x = call <8 x i8> @passthru_8i8v_from_2i32v(<2 x i32> %v)
ret <8 x i8> %x
}
define <8 x i8> @returned_vec_arg_casted(<2 x i32> %a) {
; CHECK-LABEL: @returned_vec_arg_casted(
; CHECK-NEXT: [[TMP1:%.*]] = bitcast <2 x i32> [[A:%.*]] to <8 x i8>
; CHECK-NEXT: [[X:%.*]] = call <8 x i8> @passthru_8i8v_from_2i32v(<2 x i32> [[A]])
; CHECK-NEXT: ret <8 x i8> [[TMP1]]
;
%x = call <8 x i8> @passthru_8i8v_from_2i32v(<2 x i32> %a)
ret <8 x i8> %x
}
define i32 @returned_var_arg(i32 %arg) {
; CHECK-LABEL: @returned_var_arg(
; CHECK-NEXT: [[X:%.*]] = call i32 @passthru_i32(i32 [[ARG:%.*]])
@ -48,3 +90,4 @@ define i32 @returned_var_arg_musttail(i32 %arg) {
%x = musttail call i32 @passthru_i32(i32 %arg)
ret i32 %x
}