; RUN: llc -verify-machineinstrs -mtriple=i386-linux-gnu %s -o - | FileCheck %s ; RUN: llc -verify-machineinstrs -mtriple=x86_64-linux-gnu -mattr=+sahf %s -o - | FileCheck %s ; The peephole optimizer can elide some physical register copies such as ; EFLAGS. Make sure the flags are used directly, instead of needlessly using ; lahf, when possible. @L = external global i32 @M = external global i8 declare i32 @bar(i64) ; CHECK-LABEL: plus_one ; CHECK-NOT: seto ; CHECK-NOT: lahf ; CHECK-NOT: sahf ; CHECK-NOT: pushf ; CHECK-NOT: popf ; CHECK: incl L define i1 @plus_one() { entry: %loaded_L = load i32, i32* @L %val = add nsw i32 %loaded_L, 1 ; N.B. will emit inc. store i32 %val, i32* @L %loaded_M = load i8, i8* @M %masked = and i8 %loaded_M, 8 %M_is_true = icmp ne i8 %masked, 0 %L_is_false = icmp eq i32 %val, 0 %cond = and i1 %L_is_false, %M_is_true br i1 %cond, label %exit2, label %exit exit: ret i1 true exit2: ret i1 false } ; CHECK-LABEL: plus_forty_two ; CHECK-NOT: seto ; CHECK-NOT: lahf ; CHECK-NOT: sahf ; CHECK-NOT: pushf ; CHECK-NOT: popf ; CHECK: addl $42, define i1 @plus_forty_two() { entry: %loaded_L = load i32, i32* @L %val = add nsw i32 %loaded_L, 42 ; N.B. won't emit inc. store i32 %val, i32* @L %loaded_M = load i8, i8* @M %masked = and i8 %loaded_M, 8 %M_is_true = icmp ne i8 %masked, 0 %L_is_false = icmp eq i32 %val, 0 %cond = and i1 %L_is_false, %M_is_true br i1 %cond, label %exit2, label %exit exit: ret i1 true exit2: ret i1 false } ; CHECK-LABEL: minus_one ; CHECK-NOT: seto ; CHECK-NOT: lahf ; CHECK-NOT: sahf ; CHECK-NOT: pushf ; CHECK-NOT: popf ; CHECK: decl L define i1 @minus_one() { entry: %loaded_L = load i32, i32* @L %val = add nsw i32 %loaded_L, -1 ; N.B. will emit dec. store i32 %val, i32* @L %loaded_M = load i8, i8* @M %masked = and i8 %loaded_M, 8 %M_is_true = icmp ne i8 %masked, 0 %L_is_false = icmp eq i32 %val, 0 %cond = and i1 %L_is_false, %M_is_true br i1 %cond, label %exit2, label %exit exit: ret i1 true exit2: ret i1 false } ; CHECK-LABEL: minus_forty_two ; CHECK-NOT: seto ; CHECK-NOT: lahf ; CHECK-NOT: sahf ; CHECK-NOT: pushf ; CHECK-NOT: popf ; CHECK: addl $-42, define i1 @minus_forty_two() { entry: %loaded_L = load i32, i32* @L %val = add nsw i32 %loaded_L, -42 ; N.B. won't emit dec. store i32 %val, i32* @L %loaded_M = load i8, i8* @M %masked = and i8 %loaded_M, 8 %M_is_true = icmp ne i8 %masked, 0 %L_is_false = icmp eq i32 %val, 0 %cond = and i1 %L_is_false, %M_is_true br i1 %cond, label %exit2, label %exit exit: ret i1 true exit2: ret i1 false } ; CHECK-LABEL: test_intervening_call: ; CHECK: cmpxchg ; CHECK: seto %al ; CHECK-NEXT: lahf ; CHECK: call{{[lq]}} bar ; CHECK: addb $127, %al ; CHECK-NEXT: sahf define i64 @test_intervening_call(i64* %foo, i64 %bar, i64 %baz) { ; cmpxchg sets EFLAGS, call clobbers it, then br uses EFLAGS. %cx = cmpxchg i64* %foo, i64 %bar, i64 %baz seq_cst seq_cst %v = extractvalue { i64, i1 } %cx, 0 %p = extractvalue { i64, i1 } %cx, 1 call i32 @bar(i64 %v) br i1 %p, label %t, label %f t: ret i64 42 f: ret i64 0 } ; CHECK-LABEL: test_two_live_flags: ; CHECK: cmpxchg ; CHECK: seto %al ; CHECK-NEXT: lahf ; Save result of the first cmpxchg into D. ; CHECK-NEXT: mov{{[lq]}} %[[AX:[er]ax]], %[[D:[re]d[xi]]] ; CHECK: cmpxchg ; CHECK-NEXT: sete %al ; Save result of the second cmpxchg onto the stack. ; CHECK-NEXT: push{{[lq]}} %[[AX]] ; Restore result of the first cmpxchg from D, put it back in EFLAGS. ; CHECK-NEXT: mov{{[lq]}} %[[D]], %[[AX]] ; CHECK-NEXT: addb $127, %al ; CHECK-NEXT: sahf ; Restore result of the second cmpxchg from the stack. ; CHECK-NEXT: pop{{[lq]}} %[[AX]] ; Test from EFLAGS restored from first cmpxchg, jump if that fails. ; CHECK-NEXT: jne ; Fallthrough to test the second cmpxchg's result. ; CHECK: testb %al, %al ; CHECK-NEXT: je define i64 @test_two_live_flags( i64* %foo0, i64 %bar0, i64 %baz0, i64* %foo1, i64 %bar1, i64 %baz1) { %cx0 = cmpxchg i64* %foo0, i64 %bar0, i64 %baz0 seq_cst seq_cst %p0 = extractvalue { i64, i1 } %cx0, 1 %cx1 = cmpxchg i64* %foo1, i64 %bar1, i64 %baz1 seq_cst seq_cst %p1 = extractvalue { i64, i1 } %cx1, 1 %flag = and i1 %p0, %p1 br i1 %flag, label %t, label %f t: ret i64 42 f: ret i64 0 } ; CHECK-LABEL: asm_clobbering_flags: ; CHECK: test ; CHECK-NEXT: setg ; CHECK-NEXT: #APP ; CHECK-NEXT: bsfl ; CHECK-NEXT: #NO_APP ; CHECK-NEXT: movl ; CHECK-NEXT: ret define i1 @asm_clobbering_flags(i32* %mem) { %val = load i32, i32* %mem, align 4 %cmp = icmp sgt i32 %val, 0 %res = tail call i32 asm "bsfl $1,$0", "=r,r,~{cc},~{dirflag},~{fpsr},~{flags}"(i32 %val) store i32 %res, i32* %mem, align 4 ret i1 %cmp }