158 lines
		
	
	
		
			4.7 KiB
		
	
	
	
		
			LLVM
		
	
	
	
			
		
		
	
	
			158 lines
		
	
	
		
			4.7 KiB
		
	
	
	
		
			LLVM
		
	
	
	
| ; RUN: llc -mtriple=armv7-none-eabi -mattr=+neon < %s -o - | FileCheck %s
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| 
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| ; The following functions test the use case where an X constraint is used to
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| ; add a dependency between an assembly instruction (vmsr in this case) and
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| ; another instruction. In each function, we use a different type for the
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| ; X constraint argument.
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| ;
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| ; We can something similar from the following C code:
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| ; double f1(double f, int pscr_value) {
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| ;   asm volatile("vmsr fpscr,%0" : "=X" ((f)): "r" (pscr_value));
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| ;   return f+f;
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| ; }
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| 
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| ; CHECK-LABEL: f1
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| ; CHECK: vmsr fpscr
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| ; CHECK: vadd.f64
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| 
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| define arm_aapcs_vfpcc double @f1(double %f, i32 %pscr_value) {
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| entry:
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|   %f.addr = alloca double, align 8
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|   store double %f, double* %f.addr, align 8
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|   call void asm sideeffect "vmsr fpscr,$1", "=*X,r"(double* nonnull %f.addr, i32 %pscr_value) nounwind
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|   %0 = load double, double* %f.addr, align 8
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|   %add = fadd double %0, %0
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|   ret double %add
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| }
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| 
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| ; int f2(int f, int pscr_value) {
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| ;   asm volatile("vmsr fpscr,%0" : "=X" ((f)): "r" (pscr_value));
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| ;   return f+f;
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| ; }
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| 
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| ; CHECK-LABEL: f2
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| ; CHECK: vmsr fpscr
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| ; CHECK: mul
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| define arm_aapcs_vfpcc i32 @f2(i32 %f, i32 %pscr_value) {
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| entry:
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|   %f.addr = alloca i32, align 4
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|   store i32 %f, i32* %f.addr, align 4
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|   call void asm sideeffect "vmsr fpscr,$1", "=*X,r"(i32* nonnull %f.addr, i32 %pscr_value) nounwind
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|   %0 = load i32, i32* %f.addr, align 4
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|   %mul = mul i32 %0, %0
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|   ret i32 %mul
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| }
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| 
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| 
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| ; int f3(int f, int pscr_value) {
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| ;   asm volatile("vmsr fpscr,%0" : "=X" ((f)): "r" (pscr_value));
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| ;   return f+f;
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| ; }
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| 
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| ; typedef signed char int8_t;
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| ; typedef __attribute__((neon_vector_type(8))) int8_t int8x8_t;
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| ; void f3 (void)
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| ; {
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| ;   int8x8_t vector_res_int8x8;
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| ;   unsigned int fpscr;
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| ;   asm volatile ("vmsr fpscr,%1" : "=X" ((vector_res_int8x8)) : "r" (fpscr));
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| ;   return vector_res_int8x8 * vector_res_int8x8;
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| ; }
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| 
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| ; CHECK-LABEL: f3
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| ; CHECK: vmsr fpscr
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| ; CHECK: vmul.i8
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| define arm_aapcs_vfpcc <8 x i8> @f3() {
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| entry:
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|   %vector_res_int8x8 = alloca <8 x i8>, align 8
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|   %0 = getelementptr inbounds <8 x i8>, <8 x i8>* %vector_res_int8x8, i32 0, i32 0
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|   call void asm sideeffect "vmsr fpscr,$1", "=*X,r"(<8 x i8>* nonnull %vector_res_int8x8, i32 undef) nounwind
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|   %1 = load <8 x i8>, <8 x i8>* %vector_res_int8x8, align 8
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|   %mul = mul <8 x i8> %1, %1
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|   ret <8 x i8> %mul
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| }
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| 
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| ; We can emit integer constants.
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| ; We can get this from:
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| ; void f() {
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| ;   int x = 2;
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| ;   asm volatile ("add r0, r0, %0" : : "X" (x));
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| ; }
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| ;
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| ; CHECK-LABEL: f4
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| ; CHECK: add r0, r0, #2
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| define void @f4() {
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| entry:
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|   tail call void asm sideeffect "add r0, r0, $0", "X"(i32 2)
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|   ret void
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| }
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| 
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| ; We can emit function labels. This is equivalent to the following C code:
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| ; void f(void) {
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| ;   void (*x)(void) = &foo;
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| ;   asm volatile ("bl %0" : : "X" (x));
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| ; }
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| ; CHECK-LABEL: f5
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| ; CHECK: bl f4
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| define void @f5() {
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| entry:
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|   tail call void asm sideeffect "bl $0", "X"(void ()* nonnull @f4)
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|   ret void
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| }
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| 
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| declare void @foo(...)
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| 
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| ; This tests the behavior of the X constraint when used on functions pointers,
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| ; or functions with a cast. In the first asm call we figure out that this
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| ; is a function pointer and emit the label. However, in the second asm call
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| ; we can't see through the bitcast and we end up having to lower this constraint
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| ; to something else. This is not ideal, but it is a correct behaviour according
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| ; to the definition of the X constraint.
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| ;
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| ; In this case (and other cases where we could have emitted something else),
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| ; what we're doing with the X constraint is not particularly useful either,
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| ; since the user could have used "r" in this situation for the same effect.
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| 
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| ; CHECK-LABEL: f6
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| ; CHECK: bl foo
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| ; CHECK: bl r
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| 
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| define void @f6() nounwind {
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| entry:
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|   tail call void asm sideeffect "bl $0", "X"(void (...)* @foo) nounwind
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|   tail call void asm sideeffect "bl $0", "X"(void (...)* bitcast (void ()* @f4 to void (...)*)) nounwind
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|   ret void
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| }
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| 
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| ; The following IR can be generated from C code with a function like:
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| ; void a() {
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| ;   void* a = &&A;
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| ;   asm volatile ("bl %0" : : "X" (a));
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| ;  A:
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| ;   return;
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| ; }
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| ;
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| ; Ideally this would give the block address of bb, but it requires us to see
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| ; through blockaddress, which we can't do at the moment. This might break some
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| ; existing use cases where a user would expect to get a block label and instead
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| ; gets the block address in a register. However, note that according to the
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| ; "no constraints" definition this behaviour is correct (although not very nice).
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| 
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| ; CHECK-LABEL: f7
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| ; CHECK: bl
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| define void @f7() {
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|   call void asm sideeffect "bl $0", "X"( i8* blockaddress(@f7, %bb) )
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|   br label %bb
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| bb:
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|   ret void
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| }
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| 
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| ; If we use a constraint "=*X", we should get a store back to *%x (in r0).
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| ; CHECK-LABEL: f8
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| ; CHECK: str	r{{.*}}, [r0]
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| define void @f8(i32 *%x) {
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| entry:
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|   tail call void asm sideeffect "add $0, r0, r0", "=*X"(i32 *%x)
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|   ret void
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| }
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