[SelectionDAG] fix bug in translating funnel shift with non-power-of-2 type

The bug is visible in the constant-folded x86 tests. We can't use the
negated shift amount when the type is not power-of-2:
https://rise4fun.com/Alive/US1r

...so in that case, use the regular lowering that includes a select
to guard against a shift-by-bitwidth. This path is improved by only
calculating the modulo shift amount once now.

Also, improve the rotate (with power-of-2 size) lowering to use
a negate rather than subtract from bitwidth. This improves the
codegen whether we have a rotate instruction or not (although
we can still see that we're not matching to a legal rotate in
all cases).

llvm-svn: 338592
diff --git a/llvm/test/CodeGen/X86/funnel-shift-rot.ll b/llvm/test/CodeGen/X86/funnel-shift-rot.ll
index 7953878..90574ef 100644
--- a/llvm/test/CodeGen/X86/funnel-shift-rot.ll
+++ b/llvm/test/CodeGen/X86/funnel-shift-rot.ll
@@ -92,7 +92,7 @@
 define <4 x i32> @rotl_v4i32(<4 x i32> %x, <4 x i32> %z) nounwind {
 ; X32-SSE2-LABEL: rotl_v4i32:
 ; X32-SSE2:       # %bb.0:
-; X32-SSE2-NEXT:    movdqa {{.*#+}} xmm3 = [32,32,32,32]
+; X32-SSE2-NEXT:    pxor %xmm3, %xmm3
 ; X32-SSE2-NEXT:    psubd %xmm1, %xmm3
 ; X32-SSE2-NEXT:    movdqa {{.*#+}} xmm4 = [31,31,31,31]
 ; X32-SSE2-NEXT:    pand %xmm4, %xmm3
@@ -132,7 +132,7 @@
 ; X64-AVX2-NEXT:    vpbroadcastd {{.*#+}} xmm2 = [31,31,31,31]
 ; X64-AVX2-NEXT:    vpand %xmm2, %xmm1, %xmm3
 ; X64-AVX2-NEXT:    vpsllvd %xmm3, %xmm0, %xmm3
-; X64-AVX2-NEXT:    vpbroadcastd {{.*#+}} xmm4 = [32,32,32,32]
+; X64-AVX2-NEXT:    vpxor %xmm4, %xmm4, %xmm4
 ; X64-AVX2-NEXT:    vpsubd %xmm1, %xmm4, %xmm1
 ; X64-AVX2-NEXT:    vpand %xmm2, %xmm1, %xmm1
 ; X64-AVX2-NEXT:    vpsrlvd %xmm1, %xmm0, %xmm0
@@ -226,27 +226,28 @@
 ; X32-SSE2-NEXT:    pushl %esi
 ; X32-SSE2-NEXT:    movl {{[0-9]+}}(%esp), %esi
 ; X32-SSE2-NEXT:    movl {{[0-9]+}}(%esp), %edx
-; X32-SSE2-NEXT:    movl {{[0-9]+}}(%esp), %eax
-; X32-SSE2-NEXT:    movl %eax, %ecx
+; X32-SSE2-NEXT:    movl {{[0-9]+}}(%esp), %ebx
+; X32-SSE2-NEXT:    movl %ebx, %ecx
 ; X32-SSE2-NEXT:    andl $63, %ecx
 ; X32-SSE2-NEXT:    movl %edx, %edi
 ; X32-SSE2-NEXT:    shrl %cl, %edi
-; X32-SSE2-NEXT:    movl %esi, %ebx
-; X32-SSE2-NEXT:    shrdl %cl, %edx, %ebx
-; X32-SSE2-NEXT:    xorl %ebp, %ebp
+; X32-SSE2-NEXT:    movl %esi, %ebp
+; X32-SSE2-NEXT:    shrdl %cl, %edx, %ebp
+; X32-SSE2-NEXT:    xorl %eax, %eax
 ; X32-SSE2-NEXT:    testb $32, %cl
-; X32-SSE2-NEXT:    cmovnel %edi, %ebx
-; X32-SSE2-NEXT:    cmovnel %ebp, %edi
-; X32-SSE2-NEXT:    movl $64, %ecx
-; X32-SSE2-NEXT:    subl %eax, %ecx
-; X32-SSE2-NEXT:    andl $63, %ecx
+; X32-SSE2-NEXT:    cmovnel %edi, %ebp
+; X32-SSE2-NEXT:    cmovnel %eax, %edi
+; X32-SSE2-NEXT:    negl %ebx
+; X32-SSE2-NEXT:    andl $63, %ebx
 ; X32-SSE2-NEXT:    movl %esi, %eax
+; X32-SSE2-NEXT:    movl %ebx, %ecx
 ; X32-SSE2-NEXT:    shll %cl, %eax
 ; X32-SSE2-NEXT:    shldl %cl, %esi, %edx
-; X32-SSE2-NEXT:    testb $32, %cl
+; X32-SSE2-NEXT:    testb $32, %bl
 ; X32-SSE2-NEXT:    cmovnel %eax, %edx
-; X32-SSE2-NEXT:    cmovnel %ebp, %eax
-; X32-SSE2-NEXT:    orl %ebx, %eax
+; X32-SSE2-NEXT:    movl $0, %ecx
+; X32-SSE2-NEXT:    cmovnel %ecx, %eax
+; X32-SSE2-NEXT:    orl %ebp, %eax
 ; X32-SSE2-NEXT:    orl %edi, %edx
 ; X32-SSE2-NEXT:    popl %esi
 ; X32-SSE2-NEXT:    popl %edi
@@ -270,7 +271,7 @@
 ; X32-SSE2-LABEL: rotr_v4i32:
 ; X32-SSE2:       # %bb.0:
 ; X32-SSE2-NEXT:    movdqa {{.*#+}} xmm2 = [31,31,31,31]
-; X32-SSE2-NEXT:    movdqa {{.*#+}} xmm3 = [32,32,32,32]
+; X32-SSE2-NEXT:    pxor %xmm3, %xmm3
 ; X32-SSE2-NEXT:    psubd %xmm1, %xmm3
 ; X32-SSE2-NEXT:    movdqa %xmm1, %xmm4
 ; X32-SSE2-NEXT:    pand %xmm2, %xmm4
@@ -310,7 +311,7 @@
 ; X64-AVX2-NEXT:    vpbroadcastd {{.*#+}} xmm2 = [31,31,31,31]
 ; X64-AVX2-NEXT:    vpand %xmm2, %xmm1, %xmm3
 ; X64-AVX2-NEXT:    vpsrlvd %xmm3, %xmm0, %xmm3
-; X64-AVX2-NEXT:    vpbroadcastd {{.*#+}} xmm4 = [32,32,32,32]
+; X64-AVX2-NEXT:    vpxor %xmm4, %xmm4, %xmm4
 ; X64-AVX2-NEXT:    vpsubd %xmm1, %xmm4, %xmm1
 ; X64-AVX2-NEXT:    vpand %xmm2, %xmm1, %xmm1
 ; X64-AVX2-NEXT:    vpsllvd %xmm1, %xmm0, %xmm0
@@ -396,7 +397,7 @@
 define i7 @fshl_i7() {
 ; ANY-LABEL: fshl_i7:
 ; ANY:       # %bb.0:
-; ANY-NEXT:    movb $112, %al
+; ANY-NEXT:    movb $67, %al
 ; ANY-NEXT:    ret{{[l|q]}}
   %f = call i7 @llvm.fshl.i7(i7 112, i7 112, i7 9)
   ret i7 %f
@@ -408,7 +409,7 @@
 define i7 @fshr_i7() {
 ; ANY-LABEL: fshr_i7:
 ; ANY:       # %bb.0:
-; ANY-NEXT:    movb $125, %al
+; ANY-NEXT:    movb $60, %al
 ; ANY-NEXT:    ret{{[l|q]}}
   %f = call i7 @llvm.fshr.i7(i7 113, i7 113, i7 16)
   ret i7 %f