llvm/test/CodeGen/X86/fast-isel-x86-64.ll
Preston Gurd c7b902e7fe Pad Short Functions for Intel Atom
The current Intel Atom microarchitecture has a feature whereby
when a function returns early then it is slightly faster to execute
a sequence of NOP instructions to wait until the return address is ready,
as opposed to simply stalling on the ret instruction until
the return address is ready.

When compiling for X86 Atom only, this patch will run a pass,
called "X86PadShortFunction" which will add NOP instructions where less
than four cycles elapse between function entry and return.

It includes tests.

This patch has been updated to address Nadav's review comments
- Optimize only at >= O1 and don't do optimization if -Os is set
- Stores MachineBasicBlock* instead of BBNum
- Uses DenseMap instead of std::map
- Fixes placement of braces

Patch by Andy Zhang.




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171879 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-08 18:27:24 +00:00

307 lines
6.8 KiB
LLVM

; RUN: llc < %s -mattr=-avx -fast-isel -mcpu=core2 -O0 -regalloc=fast -asm-verbose=0 -fast-isel-abort | FileCheck %s
; RUN: llc < %s -mattr=+avx -fast-isel -mcpu=core2 -O0 -regalloc=fast -asm-verbose=0 -fast-isel-abort | FileCheck %s --check-prefix=AVX
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
target triple = "x86_64-apple-darwin10.0.0"
; Make sure that fast-isel folds the immediate into the binop even though it
; is non-canonical.
define i32 @test1(i32 %i) nounwind ssp {
%and = and i32 8, %i
ret i32 %and
}
; CHECK: test1:
; CHECK: andl $8,
; rdar://9289512 - The load should fold into the compare.
define void @test2(i64 %x) nounwind ssp {
entry:
%x.addr = alloca i64, align 8
store i64 %x, i64* %x.addr, align 8
%tmp = load i64* %x.addr, align 8
%cmp = icmp sgt i64 %tmp, 42
br i1 %cmp, label %if.then, label %if.end
if.then: ; preds = %entry
br label %if.end
if.end: ; preds = %if.then, %entry
ret void
; CHECK: test2:
; CHECK: movq %rdi, -8(%rsp)
; CHECK: cmpq $42, -8(%rsp)
}
@G = external global i32
define i64 @test3() nounwind {
%A = ptrtoint i32* @G to i64
ret i64 %A
; CHECK: test3:
; CHECK: movq _G@GOTPCREL(%rip), %rax
; CHECK-NEXT: ret
}
; rdar://9289558
@rtx_length = external global [153 x i8]
define i32 @test4(i64 %idxprom9) nounwind {
%arrayidx10 = getelementptr inbounds [153 x i8]* @rtx_length, i32 0, i64 %idxprom9
%tmp11 = load i8* %arrayidx10, align 1
%conv = zext i8 %tmp11 to i32
ret i32 %conv
; CHECK: test4:
; CHECK: movq _rtx_length@GOTPCREL(%rip), %rax
; CHECK-NEXT: movzbl (%rax,%rdi), %eax
; CHECK-NEXT: ret
}
; PR3242 - Out of range shifts should not be folded by fastisel.
define void @test5(i32 %x, i32* %p) nounwind {
%y = ashr i32 %x, 50000
store i32 %y, i32* %p
ret void
; CHECK: test5:
; CHECK: movl $50000, %ecx
; CHECK: sarl %cl, %edi
; CHECK: ret
}
; rdar://9289501 - fast isel should fold trivial multiplies to shifts.
define i64 @test6(i64 %x) nounwind ssp {
entry:
%mul = mul nsw i64 %x, 8
ret i64 %mul
; CHECK: test6:
; CHECK: shlq $3, %rdi
}
define i32 @test7(i32 %x) nounwind ssp {
entry:
%mul = mul nsw i32 %x, 8
ret i32 %mul
; CHECK: test7:
; CHECK: shll $3, %edi
}
; rdar://9289507 - folding of immediates into 64-bit operations.
define i64 @test8(i64 %x) nounwind ssp {
entry:
%add = add nsw i64 %x, 7
ret i64 %add
; CHECK: test8:
; CHECK: addq $7, %rdi
}
define i64 @test9(i64 %x) nounwind ssp {
entry:
%add = mul nsw i64 %x, 7
ret i64 %add
; CHECK: test9:
; CHECK: imulq $7, %rdi, %rax
}
; rdar://9297011 - Don't reject udiv by a power of 2.
define i32 @test10(i32 %X) nounwind {
%Y = udiv i32 %X, 8
ret i32 %Y
; CHECK: test10:
; CHECK: shrl $3,
}
define i32 @test11(i32 %X) nounwind {
%Y = sdiv exact i32 %X, 8
ret i32 %Y
; CHECK: test11:
; CHECK: sarl $3,
}
; rdar://9297006 - Trunc to bool.
define void @test12(i8 %tmp) nounwind ssp noredzone {
entry:
%tobool = trunc i8 %tmp to i1
br i1 %tobool, label %if.then, label %if.end
if.then: ; preds = %entry
call void @test12(i8 0) noredzone
br label %if.end
if.end: ; preds = %if.then, %entry
ret void
; CHECK: test12:
; CHECK: testb $1,
; CHECK-NEXT: je L
; CHECK-NEXT: movl $0, %edi
; CHECK-NEXT: callq
}
declare void @test13f(i1 %X)
define void @test13() nounwind {
call void @test13f(i1 0)
ret void
; CHECK: test13:
; CHECK: movl $0, %edi
; CHECK-NEXT: callq
}
; rdar://9297003 - fast isel bails out on all functions taking bools
define void @test14(i8 %tmp) nounwind ssp noredzone {
entry:
%tobool = trunc i8 %tmp to i1
call void @test13f(i1 zeroext %tobool) noredzone
ret void
; CHECK: test14:
; CHECK: andb $1,
; CHECK: callq
}
declare void @llvm.memcpy.p0i8.p0i8.i64(i8*, i8*, i64, i32, i1)
; rdar://9289488 - fast-isel shouldn't bail out on llvm.memcpy
define void @test15(i8* %a, i8* %b) nounwind {
call void @llvm.memcpy.p0i8.p0i8.i64(i8* %a, i8* %b, i64 4, i32 4, i1 false)
ret void
; CHECK: test15:
; CHECK-NEXT: movl (%rsi), %eax
; CHECK-NEXT: movl %eax, (%rdi)
; CHECK-NEXT: ret
}
; Handling for varargs calls
declare void @test16callee(...) nounwind
define void @test16() nounwind {
; CHECK: test16:
; CHECK: movl $1, %edi
; CHECK: movb $0, %al
; CHECK: callq _test16callee
call void (...)* @test16callee(i32 1)
br label %block2
block2:
; CHECK: movabsq $1
; CHECK: cvtsi2sdq {{.*}} %xmm0
; CHECK: movb $1, %al
; CHECK: callq _test16callee
; AVX: movabsq $1
; AVX: vmovsd LCP{{.*}}_{{.*}}(%rip), %xmm0
; AVX: movb $1, %al
; AVX: callq _test16callee
call void (...)* @test16callee(double 1.000000e+00)
ret void
}
declare void @foo() unnamed_addr ssp align 2
; Verify that we don't fold the load into the compare here. That would move it
; w.r.t. the call.
define i32 @test17(i32 *%P) ssp nounwind {
entry:
%tmp = load i32* %P
%cmp = icmp ne i32 %tmp, 5
call void @foo()
br i1 %cmp, label %if.then, label %if.else
if.then: ; preds = %entry
ret i32 1
if.else: ; preds = %entry
ret i32 2
; CHECK: test17:
; CHECK: movl (%rdi), %eax
; CHECK: callq _foo
; CHECK: cmpl $5, %eax
; CHECK-NEXT: je
}
; Check that 0.0 is materialized using xorps
define void @test18(float* %p1) {
store float 0.0, float* %p1
ret void
; CHECK: test18:
; CHECK: xorps
}
; Without any type hints, doubles use the smaller xorps instead of xorpd.
define void @test19(double* %p1) {
store double 0.0, double* %p1
ret void
; CHECK: test19:
; CHECK: xorps
}
; Check that we fast-isel sret
%struct.a = type { i64, i64, i64 }
define void @test20() nounwind ssp {
entry:
%tmp = alloca %struct.a, align 8
call void @test20sret(%struct.a* sret %tmp)
ret void
; CHECK: test20:
; CHECK: leaq (%rsp), %rdi
; CHECK: callq _test20sret
}
declare void @test20sret(%struct.a* sret)
; Check that -0.0 is not materialized using xor
define void @test21(double* %p1) {
store double -0.0, double* %p1
ret void
; CHECK: test21:
; CHECK-NOT: xor
; CHECK: movsd LCPI
}
; Check that immediate arguments to a function
; do not cause massive spilling and are used
; as immediates just before the call.
define void @test22() nounwind {
entry:
call void @foo22(i32 0)
call void @foo22(i32 1)
call void @foo22(i32 2)
call void @foo22(i32 3)
ret void
; CHECK: test22:
; CHECK: movl $0, %edi
; CHECK: callq _foo22
; CHECK: movl $1, %edi
; CHECK: callq _foo22
; CHECK: movl $2, %edi
; CHECK: callq _foo22
; CHECK: movl $3, %edi
; CHECK: callq _foo22
}
declare void @foo22(i32)
; PR13563
define void @test23(i8* noalias sret %result) {
%a = alloca i8
%b = call i8* @foo23()
ret void
; CHECK: test23:
; CHECK: call
; CHECK: movq %rdi, %rax
; CHECK: ret
}
declare i8* @foo23()