[X86][SSE] Attempt to merge single-op hops for slow targets.
For slow-hop targets, see if any single-op hops are duplicating work already done on another (dual-op) hop, which can sometimes occur as isHorizontalBinOp tries to find potential duplicates (but can't merge them itself). If so, reuse the other hop and shuffle the result.
diff --git a/llvm/test/CodeGen/X86/horizontal-sum.ll b/llvm/test/CodeGen/X86/horizontal-sum.ll
index dbccdbd..89434cc 100644
--- a/llvm/test/CodeGen/X86/horizontal-sum.ll
+++ b/llvm/test/CodeGen/X86/horizontal-sum.ll
@@ -270,16 +270,13 @@
; AVX1-SLOW-NEXT: vaddps %xmm0, %xmm1, %xmm0
; AVX1-SLOW-NEXT: vunpcklps {{.*#+}} xmm0 = xmm8[0],xmm0[0],xmm8[1],xmm0[1]
; AVX1-SLOW-NEXT: vhaddps %xmm3, %xmm2, %xmm1
-; AVX1-SLOW-NEXT: vhaddps %xmm2, %xmm2, %xmm2
-; AVX1-SLOW-NEXT: vhaddps %xmm3, %xmm3, %xmm3
-; AVX1-SLOW-NEXT: vinsertps {{.*#+}} xmm2 = xmm2[1],xmm3[1],zero,zero
-; AVX1-SLOW-NEXT: vhaddps %xmm4, %xmm4, %xmm3
-; AVX1-SLOW-NEXT: vhaddps %xmm5, %xmm5, %xmm4
-; AVX1-SLOW-NEXT: vshufps {{.*#+}} xmm1 = xmm1[0,2],xmm3[0,1]
-; AVX1-SLOW-NEXT: vinsertps {{.*#+}} xmm1 = xmm1[0,1,2],xmm4[0]
-; AVX1-SLOW-NEXT: vshufps {{.*#+}} xmm2 = xmm2[0,1],xmm3[1,3]
-; AVX1-SLOW-NEXT: vinsertps {{.*#+}} xmm2 = xmm2[0,1,2],xmm4[1]
-; AVX1-SLOW-NEXT: vaddps %xmm2, %xmm1, %xmm1
+; AVX1-SLOW-NEXT: vhaddps %xmm4, %xmm4, %xmm2
+; AVX1-SLOW-NEXT: vhaddps %xmm5, %xmm5, %xmm3
+; AVX1-SLOW-NEXT: vshufps {{.*#+}} xmm4 = xmm1[0,2],xmm2[0,1]
+; AVX1-SLOW-NEXT: vinsertps {{.*#+}} xmm4 = xmm4[0,1,2],xmm3[0]
+; AVX1-SLOW-NEXT: vshufps {{.*#+}} xmm1 = xmm1[1,3],xmm2[1,1]
+; AVX1-SLOW-NEXT: vinsertps {{.*#+}} xmm1 = xmm1[0,1,2],xmm3[1]
+; AVX1-SLOW-NEXT: vaddps %xmm1, %xmm4, %xmm1
; AVX1-SLOW-NEXT: vmovlhps {{.*#+}} xmm0 = xmm0[0],xmm1[0]
; AVX1-SLOW-NEXT: vpermilpd {{.*#+}} xmm1 = xmm1[1,0]
; AVX1-SLOW-NEXT: vinsertf128 $1, %xmm1, %ymm0, %ymm1
@@ -423,15 +420,14 @@
; SSSE3-SLOW-NEXT: paddd %xmm1, %xmm2
; SSSE3-SLOW-NEXT: punpckldq {{.*#+}} xmm0 = xmm0[0],xmm2[0],xmm0[1],xmm2[1]
; SSSE3-SLOW-NEXT: phaddd %xmm3, %xmm8
-; SSSE3-SLOW-NEXT: movdqa %xmm5, %xmm1
; SSSE3-SLOW-NEXT: phaddd %xmm4, %xmm5
-; SSSE3-SLOW-NEXT: phaddd %xmm4, %xmm4
-; SSSE3-SLOW-NEXT: phaddd %xmm1, %xmm1
-; SSSE3-SLOW-NEXT: shufps {{.*#+}} xmm1 = xmm1[1,1],xmm4[1,1]
-; SSSE3-SLOW-NEXT: movdqa %xmm8, %xmm2
-; SSSE3-SLOW-NEXT: shufps {{.*#+}} xmm2 = xmm2[0,2],xmm5[2,0]
-; SSSE3-SLOW-NEXT: shufps {{.*#+}} xmm8 = xmm8[1,3],xmm1[2,0]
-; SSSE3-SLOW-NEXT: paddd %xmm2, %xmm8
+; SSSE3-SLOW-NEXT: pshufd {{.*#+}} xmm1 = xmm5[2,3,2,3]
+; SSSE3-SLOW-NEXT: pshufd {{.*#+}} xmm2 = xmm5[0,1,0,1]
+; SSSE3-SLOW-NEXT: shufps {{.*#+}} xmm2 = xmm2[1,1],xmm1[1,1]
+; SSSE3-SLOW-NEXT: movdqa %xmm8, %xmm1
+; SSSE3-SLOW-NEXT: shufps {{.*#+}} xmm1 = xmm1[0,2],xmm5[2,0]
+; SSSE3-SLOW-NEXT: shufps {{.*#+}} xmm8 = xmm8[1,3],xmm2[2,0]
+; SSSE3-SLOW-NEXT: paddd %xmm1, %xmm8
; SSSE3-SLOW-NEXT: punpcklqdq {{.*#+}} xmm0 = xmm0[0],xmm8[0]
; SSSE3-SLOW-NEXT: phaddd %xmm6, %xmm6
; SSSE3-SLOW-NEXT: phaddd %xmm7, %xmm7
@@ -470,30 +466,27 @@
; AVX1-SLOW-NEXT: vphaddd %xmm1, %xmm1, %xmm1
; AVX1-SLOW-NEXT: vpshufd {{.*#+}} xmm0 = xmm1[1,1,1,1]
; AVX1-SLOW-NEXT: vpaddd %xmm0, %xmm1, %xmm0
-; AVX1-SLOW-NEXT: vpunpckldq {{.*#+}} xmm8 = xmm8[0],xmm0[0],xmm8[1],xmm0[1]
+; AVX1-SLOW-NEXT: vpunpckldq {{.*#+}} xmm0 = xmm8[0],xmm0[0],xmm8[1],xmm0[1]
; AVX1-SLOW-NEXT: vphaddd %xmm3, %xmm2, %xmm1
-; AVX1-SLOW-NEXT: vpshufd {{.*#+}} xmm1 = xmm1[0,2,1,3]
-; AVX1-SLOW-NEXT: vphaddd %xmm2, %xmm2, %xmm2
-; AVX1-SLOW-NEXT: vphaddd %xmm3, %xmm3, %xmm3
-; AVX1-SLOW-NEXT: vphaddd %xmm4, %xmm4, %xmm4
-; AVX1-SLOW-NEXT: vphaddd %xmm5, %xmm5, %xmm5
-; AVX1-SLOW-NEXT: vpunpcklqdq {{.*#+}} xmm1 = xmm1[0],xmm4[0]
-; AVX1-SLOW-NEXT: vpshufd {{.*#+}} xmm0 = xmm5[0,0,0,0]
-; AVX1-SLOW-NEXT: vpblendw {{.*#+}} xmm0 = xmm1[0,1,2,3,4,5],xmm0[6,7]
-; AVX1-SLOW-NEXT: vpshufd {{.*#+}} xmm1 = xmm2[1,1,1,1]
-; AVX1-SLOW-NEXT: vpblendw {{.*#+}} xmm1 = xmm1[0,1],xmm3[2,3],xmm1[4,5,6,7]
-; AVX1-SLOW-NEXT: vinsertps {{.*#+}} xmm1 = xmm1[0,1],xmm4[1],zero
-; AVX1-SLOW-NEXT: vinsertps {{.*#+}} xmm1 = xmm1[0,1,2],xmm5[1]
-; AVX1-SLOW-NEXT: vpaddd %xmm1, %xmm0, %xmm0
-; AVX1-SLOW-NEXT: vpunpcklqdq {{.*#+}} xmm1 = xmm8[0],xmm0[0]
-; AVX1-SLOW-NEXT: vpshufd {{.*#+}} xmm0 = xmm0[2,3,2,3]
-; AVX1-SLOW-NEXT: vinsertf128 $1, %xmm0, %ymm1, %ymm0
+; AVX1-SLOW-NEXT: vpshufd {{.*#+}} xmm2 = xmm1[0,2,1,3]
+; AVX1-SLOW-NEXT: vphaddd %xmm4, %xmm4, %xmm3
+; AVX1-SLOW-NEXT: vphaddd %xmm5, %xmm5, %xmm4
+; AVX1-SLOW-NEXT: vpunpcklqdq {{.*#+}} xmm2 = xmm2[0],xmm3[0]
+; AVX1-SLOW-NEXT: vpshufd {{.*#+}} xmm5 = xmm4[0,0,0,0]
+; AVX1-SLOW-NEXT: vpblendw {{.*#+}} xmm2 = xmm2[0,1,2,3,4,5],xmm5[6,7]
+; AVX1-SLOW-NEXT: vpshufd {{.*#+}} xmm1 = xmm1[1,3,1,1]
+; AVX1-SLOW-NEXT: vinsertps {{.*#+}} xmm1 = xmm1[0,1],xmm3[1],zero
+; AVX1-SLOW-NEXT: vinsertps {{.*#+}} xmm1 = xmm1[0,1,2],xmm4[1]
+; AVX1-SLOW-NEXT: vpaddd %xmm1, %xmm2, %xmm1
+; AVX1-SLOW-NEXT: vpunpcklqdq {{.*#+}} xmm0 = xmm0[0],xmm1[0]
+; AVX1-SLOW-NEXT: vpshufd {{.*#+}} xmm1 = xmm1[2,3,2,3]
+; AVX1-SLOW-NEXT: vinsertf128 $1, %xmm1, %ymm0, %ymm1
; AVX1-SLOW-NEXT: vphaddd %xmm6, %xmm6, %xmm2
; AVX1-SLOW-NEXT: vphaddd %xmm7, %xmm7, %xmm3
; AVX1-SLOW-NEXT: vphaddd %xmm3, %xmm2, %xmm2
; AVX1-SLOW-NEXT: vpshufd {{.*#+}} xmm2 = xmm2[0,2,2,3]
-; AVX1-SLOW-NEXT: vinsertf128 $1, %xmm2, %ymm1, %ymm1
-; AVX1-SLOW-NEXT: vshufpd {{.*#+}} ymm0 = ymm0[0],ymm1[1],ymm0[2],ymm1[2]
+; AVX1-SLOW-NEXT: vinsertf128 $1, %xmm2, %ymm0, %ymm0
+; AVX1-SLOW-NEXT: vshufpd {{.*#+}} ymm0 = ymm1[0],ymm0[1],ymm1[2],ymm0[2]
; AVX1-SLOW-NEXT: retq
;
; AVX1-FAST-LABEL: pair_sum_v8i32_v4i32:
