Add intermediate subtract instructions to reassociation worklist.

[oota-llvm.git] / test / Transforms / Reassociate / reassoc-intermediate-fnegs.ll

diff --git a/test/Transforms/Reassociate/reassoc-intermediate-fnegs.ll b/test/Transforms/Reassociate/reassoc-intermediate-fnegs.ll
new file mode 100644 (file)
index 0000000..c2cdffc
--- /dev/null
+++ b/test/Transforms/Reassociate/reassoc-intermediate-fnegs.ll
@@ -0,0 +1,31 @@
+; RUN: opt < %s -reassociate -S | FileCheck %s
+; CHECK-LABEL: faddsubAssoc1
+; CHECK: [[TMP1:%tmp.*]] = fmul fast half %a, 0xH4500
+; CHECK: [[TMP2:%tmp.*]] = fmul fast half %b, 0xH4500
+; CHECK: fsub fast half [[TMP2]], [[TMP1]]
+; CHECK: ret
+; Input is A op (B op C)
+define half @faddsubAssoc1(half %a, half %b) {
+  %tmp1 = fmul fast half %b, 0xH4200 ; 3*b
+  %tmp2 = fmul fast half %a, 0xH4500 ; 5*a
+  %tmp3 = fmul fast half %b, 0xH4000 ; 2*b
+  %tmp4 = fsub fast half %tmp2, %tmp1 ; 5 * a - 3 * b
+  %tmp5 = fsub fast half %tmp3, %tmp4 ; 2 * b - ( 5 * a - 3 * b)
+  ret half %tmp5 ; = 5 * (b - a)
+}
+
+; CHECK-LABEL: faddsubAssoc2
+; CHECK: [[TMP1:%tmp.*]] = fmul fast half %a, 0xH4500
+; CHECK: [[TMP2:%tmp.*]] = fmul fast half %b, 0xH3C00
+; CHECK: fadd fast half [[TMP2]], [[TMP1]]
+; CHECK: ret
+; Input is (A op B) op C
+define half @faddsubAssoc2(half %a, half %b) {
+  %tmp1 = fmul fast half %b, 0xH4200 ; 3*b
+  %tmp2 = fmul fast half %a, 0xH4500 ; 5*a
+  %tmp3 = fmul fast half %b, 0xH4000 ; 2*b
+  %tmp4 = fadd fast half %tmp2, %tmp1 ; 5 * a + 3 * b
+  %tmp5 = fsub fast half %tmp4, %tmp3 ; (5 * a + 3 * b) - (2 * b)
+  ret half %tmp5 ; = 5 * a + b
+}
+