1; NOTE: Assertions have been autogenerated by utils/update_test_checks.py 2; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=avx | FileCheck %s 3 4declare double @sin(double %f) 5 6; When the subs are strict, they can't be removed because of signed zero. 7 8define double @strict(double %e) nounwind { 9; CHECK-LABEL: strict: 10; CHECK: # BB#0: 11; CHECK-NEXT: pushq %rax 12; CHECK-NEXT: vxorpd %xmm1, %xmm1, %xmm1 13; CHECK-NEXT: vsubsd %xmm0, %xmm1, %xmm0 14; CHECK-NEXT: callq sin 15; CHECK-NEXT: vxorpd %xmm1, %xmm1, %xmm1 16; CHECK-NEXT: vsubsd %xmm0, %xmm1, %xmm0 17; CHECK-NEXT: popq %rax 18; CHECK-NEXT: retq 19; 20 %f = fsub double 0.0, %e 21 %g = call double @sin(double %f) readonly 22 %h = fsub double 0.0, %g 23 ret double %h 24} 25 26; 'fast' implies no-signed-zeros, so the negates fold away. 27; The 'sin' does not need any fast-math-flags for this transform. 28 29define double @fast(double %e) nounwind { 30; CHECK-LABEL: fast: 31; CHECK: # BB#0: 32; CHECK-NEXT: jmp sin 33; 34 %f = fsub fast double 0.0, %e 35 %g = call double @sin(double %f) readonly 36 %h = fsub fast double 0.0, %g 37 ret double %h 38} 39 40; No-signed-zeros is all that we need for this transform. 41 42define double @nsz(double %e) nounwind { 43; CHECK-LABEL: nsz: 44; CHECK: # BB#0: 45; CHECK-NEXT: jmp sin 46; 47 %f = fsub nsz double 0.0, %e 48 %g = call double @sin(double %f) readonly 49 %h = fsub nsz double 0.0, %g 50 ret double %h 51} 52 53; The 1st negate is strict, so we can't kill that sub, but the 2nd disappears. 54 55define double @semi_strict1(double %e) nounwind { 56; CHECK-LABEL: semi_strict1: 57; CHECK: # BB#0: 58; CHECK-NEXT: pushq %rax 59; CHECK-NEXT: vxorpd %xmm1, %xmm1, %xmm1 60; CHECK-NEXT: vsubsd %xmm0, %xmm1, %xmm0 61; CHECK-NEXT: callq sin 62; CHECK-NEXT: vxorpd {{.*}}(%rip), %xmm0, %xmm0 63; CHECK-NEXT: popq %rax 64; CHECK-NEXT: retq 65; 66 %f = fsub double 0.0, %e 67 %g = call double @sin(double %f) readonly 68 %h = fsub nsz double 0.0, %g 69 ret double %h 70} 71 72; The 2nd negate is strict, so we can't kill it. It becomes an add of zero instead. 73 74define double @semi_strict2(double %e) nounwind { 75; CHECK-LABEL: semi_strict2: 76; CHECK: # BB#0: 77; CHECK-NEXT: pushq %rax 78; CHECK-NEXT: callq sin 79; CHECK-NEXT: vxorpd %xmm1, %xmm1, %xmm1 80; CHECK-NEXT: vaddsd %xmm1, %xmm0, %xmm0 81; CHECK-NEXT: popq %rax 82; CHECK-NEXT: retq 83; 84 %f = fsub nsz double 0.0, %e 85 %g = call double @sin(double %f) readonly 86 %h = fsub double 0.0, %g 87 ret double %h 88} 89 90; FIXME: 91; Auto-upgrade function attribute to IR-level fast-math-flags. 92 93define double @fn_attr(double %e) nounwind #0 { 94; CHECK-LABEL: fn_attr: 95; CHECK: # BB#0: 96; CHECK-NEXT: jmp sin 97; 98 %f = fsub double 0.0, %e 99 %g = call double @sin(double %f) readonly 100 %h = fsub double 0.0, %g 101 ret double %h 102} 103 104attributes #0 = { "unsafe-fp-math"="true" } 105 106