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llvm-mirror/test/CodeGen/X86/tailccfp2.ll
Reid Kleckner a973c0bd85 [X86] Add new calling convention that guarantees tail call optimization
When the target option GuaranteedTailCallOpt is specified, calls with
the fastcc calling convention will be transformed into tail calls if
they are in tail position. This diff adds a new calling convention,
tailcc, currently supported only on X86, which behaves the same way as
fastcc, except that the GuaranteedTailCallOpt flag does not need to
enabled in order to enable tail call optimization.

Patch by Dwight Guth <dwight.guth@runtimeverification.com>!

Reviewed By: lebedev.ri, paquette, rnk

Differential Revision: https://reviews.llvm.org/D67855

llvm-svn: 373976
2019-10-07 22:28:58 +00:00

28 lines
721 B
LLVM

; RUN: llc < %s -mtriple=i686-- | FileCheck %s
declare i32 @putchar(i32)
define tailcc i32 @checktail(i32 %x, i32* %f, i32 %g) nounwind {
; CHECK-LABEL: checktail:
%tmp1 = icmp sgt i32 %x, 0
br i1 %tmp1, label %if-then, label %if-else
if-then:
%fun_ptr = bitcast i32* %f to i32(i32, i32*, i32)*
%arg1 = add i32 %x, -1
call i32 @putchar(i32 90)
; CHECK: jmpl *%e{{.*}}
%res = tail call tailcc i32 %fun_ptr( i32 %arg1, i32 * %f, i32 %g)
ret i32 %res
if-else:
ret i32 %x
}
define i32 @main() nounwind {
%f = bitcast i32 (i32, i32*, i32)* @checktail to i32*
%res = tail call tailcc i32 @checktail( i32 10, i32* %f,i32 10)
ret i32 %res
}