CodeGen peephole: fold redundant phys reg copies

[oota-llvm.git] / test / CodeGen / X86 / fdiv-combine.ll

diff --git a/test/CodeGen/X86/fdiv-combine.ll b/test/CodeGen/X86/fdiv-combine.ll
index 279bb0624ace6aff31564e96a96af9769b6dada5..d9d9ac401fb50ae594b45fc097f0858692583c8e 100644 (file)
--- a/test/CodeGen/X86/fdiv-combine.ll
+++ b/test/CodeGen/X86/fdiv-combine.ll
@@ -1,9 +1,11 @@
-; RUN: llc < %s -mtriple=x86_64-unknown-unknown | FileCheck %s
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mcpu=x86-64 | FileCheck %s
 
-; Anything more than one division using a single divisor operand
+; More than one 'arcp' division using a single divisor operand
 ; should be converted into a reciprocal and multiplication.
 
-define float @div1_arcp(float %x, float %y, float %z) #0 {
+; Don't do anything for just one division.
+
+define float @div1_arcp(float %x, float %y, float %z) {
 ; CHECK-LABEL: div1_arcp:
 ; CHECK:       # BB#0:
 ; CHECK-NEXT:    divss %xmm1, %xmm0
@@ -12,8 +14,10 @@ define float @div1_arcp(float %x, float %y, float %z) #0 {
   ret float %div1
 }
 
-define float @div2_arcp(float %x, float %y, float %z) #0 {
-; CHECK-LABEL: div2_arcp:
+; All math instructions are 'arcp', so optimize.
+
+define float @div2_arcp_all(float %x, float %y, float %z) {
+; CHECK-LABEL: div2_arcp_all:
 ; CHECK:       # BB#0:
 ; CHECK-NEXT:    movss {{.*#+}} xmm3 = mem[0],zero,zero,zero
 ; CHECK-NEXT:    divss %xmm2, %xmm3
@@ -27,5 +31,86 @@ define float @div2_arcp(float %x, float %y, float %z) #0 {
   ret float %div2
 }
 
-; FIXME: If the backend understands 'arcp', then this attribute is unnecessary.
-attributes #0 = { "unsafe-fp-math"="true" }
+; The first division is not 'arcp', so do not optimize.
+
+define float @div2_arcp_partial1(float %x, float %y, float %z) {
+; CHECK-LABEL: div2_arcp_partial1:
+; CHECK:       # BB#0:
+; CHECK-NEXT:    divss %xmm2, %xmm0
+; CHECK-NEXT:    mulss %xmm1, %xmm0
+; CHECK-NEXT:    divss %xmm2, %xmm0
+; CHECK-NEXT:    retq
+  %div1 = fdiv float %x, %z
+  %mul = fmul arcp float %div1, %y
+  %div2 = fdiv arcp float %mul, %z
+  ret float %div2
+}
+
+; The second division is not 'arcp', so do not optimize.
+
+define float @div2_arcp_partial2(float %x, float %y, float %z) {
+; CHECK-LABEL: div2_arcp_partial2:
+; CHECK:       # BB#0:
+; CHECK-NEXT:    divss %xmm2, %xmm0
+; CHECK-NEXT:    mulss %xmm1, %xmm0
+; CHECK-NEXT:    divss %xmm2, %xmm0
+; CHECK-NEXT:    retq
+  %div1 = fdiv arcp float %x, %z
+  %mul = fmul arcp float %div1, %y
+  %div2 = fdiv float %mul, %z
+  ret float %div2
+}
+
+; The multiply is not 'arcp', but that does not prevent optimizing the divisions.
+
+define float @div2_arcp_partial3(float %x, float %y, float %z) {
+; CHECK-LABEL: div2_arcp_partial3:
+; CHECK:       # BB#0:
+; CHECK-NEXT:    movss {{.*#+}} xmm3 = mem[0],zero,zero,zero
+; CHECK-NEXT:    divss %xmm2, %xmm3
+; CHECK-NEXT:    mulss %xmm3, %xmm0
+; CHECK-NEXT:    mulss %xmm1, %xmm0
+; CHECK-NEXT:    mulss %xmm3, %xmm0
+; CHECK-NEXT:    retq
+  %div1 = fdiv arcp float %x, %z
+  %mul = fmul float %div1, %y
+  %div2 = fdiv arcp float %mul, %z
+  ret float %div2
+}
+
+; If the reciprocal is already calculated, we should not
+; generate an extra multiplication by 1.0. 
+
+define double @div3_arcp(double %x, double %y, double %z) {
+; CHECK-LABEL: div3_arcp:
+; CHECK:       # BB#0:
+; CHECK-NEXT:    movsd{{.*#+}} xmm2 = mem[0],zero
+; CHECK-NEXT:    divsd %xmm1, %xmm2
+; CHECK-NEXT:    mulsd %xmm2, %xmm0
+; CHECK-NEXT:    addsd %xmm2, %xmm0
+; CHECK-NEXT:    retq
+  %div1 = fdiv fast double 1.0, %y
+  %div2 = fdiv fast double %x, %y
+  %ret = fadd fast double %div2, %div1
+  ret double %ret
+}
+
+define void @PR24141() {
+; CHECK-LABEL: PR24141:
+; CHECK:       callq
+; CHECK-NEXT:  divsd
+; CHECK-NEXT:  jmp
+entry:
+  br label %while.body
+
+while.body:
+  %x.0 = phi double [ undef, %entry ], [ %div, %while.body ]
+  %call = call { double, double } @g(double %x.0)
+  %xv0 = extractvalue { double, double } %call, 0
+  %xv1 = extractvalue { double, double } %call, 1
+  %div = fdiv arcp double %xv0, %xv1
+  br label %while.body
+}
+
+declare { double, double } @g(double)
+