One readme entry is done, one is really easy (Evan, want to investigate

eliminating the llvm.x86.sse2.loadl.pd intrinsic?), one shuffle optzn
may be done (if shufps is better than pinsw, Evan, please review), and
we already know about LICM of simple instructions.

llvm-svn: 45407

lib/Target/X86/README-SSE.txt

@@ -456,6 +456,18 @@ icc generates:
 So icc is smart enough to know that B is in memory so it doesn't load it and
 store it back to stack.
 
+This should be fixed by eliminating the llvm.x86.sse2.loadl.pd intrinsic, 
+lowering it to a load+insertelement instead.  Already match the load+shuffle 
+as movlpd, so this should be easy.  We already get optimal code for:
+
+define void @test2(<2 x double>* %r, <2 x double>* %A, double %B) {
+entry:
+	%tmp2 = load <2 x double>* %A, align 16
+	%tmp8 = insertelement <2 x double> %tmp2, double %B, i32 0
+	store <2 x double> %tmp8, <2 x double>* %r, align 16
+	ret void
+}
+
 //===---------------------------------------------------------------------===//
 
 __m128d test1( __m128d A, __m128d B) {
@@ -476,10 +488,10 @@ Don't know if unpckhpd is faster. But it is shorter.
 
 This code generates ugly code, probably due to costs being off or something:
 
-void %test(float* %P, <4 x float>* %P2 ) {
+define void @test(float* %P, <4 x float>* %P2 ) {
         %xFloat0.688 = load float* %P
-        %loadVector37.712 = load <4 x float>* %P2
-        %inFloat3.713 = insertelement <4 x float> %loadVector37.712, float 0.000000e+00, uint 3
+        %tmp = load <4 x float>* %P2
+        %inFloat3.713 = insertelement <4 x float> %tmp, float 0.0, i32 3
         store <4 x float> %inFloat3.713, <4 x float>* %P2
         ret void
 }
@@ -487,17 +499,16 @@ void %test(float* %P, <4 x float>* %P2 ) {
 Generates:
 
 _test:
-        pxor %xmm0, %xmm0
-        movd %xmm0, %eax        ;; EAX = 0!
-        movl 8(%esp), %ecx
-        movaps (%ecx), %xmm0
-        pinsrw $6, %eax, %xmm0
-        shrl $16, %eax          ;; EAX = 0 again!
-        pinsrw $7, %eax, %xmm0
-        movaps %xmm0, (%ecx)
-        ret
+	movl	8(%esp), %eax
+	movaps	(%eax), %xmm0
+	pxor	%xmm1, %xmm1
+	movaps	%xmm0, %xmm2
+	shufps	$50, %xmm1, %xmm2
+	shufps	$132, %xmm2, %xmm0
+	movaps	%xmm0, (%eax)
+	ret
 
-It would be better to generate:
+Would it be better to generate:
 
 _test:
         movl 8(%esp), %ecx
@@ -508,7 +519,7 @@ _test:
         movaps %xmm0, (%ecx)
         ret
 
-or use pxor (to make a zero vector) and shuffle (to insert it).
+?
 
 //===---------------------------------------------------------------------===//
 
@@ -576,32 +587,6 @@ swizzle:
 
 //===---------------------------------------------------------------------===//
 
-This code:
-
-#include <emmintrin.h>
-__m128i test(long long i) { return _mm_cvtsi64x_si128(i); }
-
-Should turn into a single 'movq %rdi, %xmm0' instruction.  Instead, we 
-get this (on x86-64):
-
-_test:
-	movd %rdi, %xmm1
-	xorps %xmm0, %xmm0
-	movsd %xmm1, %xmm0
-	ret
-
-The LLVM IR is:
-
-target triple = "x86_64-apple-darwin8"
-define <2 x i64> @test(i64 %i) {
-entry:
-	%tmp10 = insertelement <2 x i64> undef, i64 %i, i32 0	
-	%tmp11 = insertelement <2 x i64> %tmp10, i64 0, i32 1
-	ret <2 x i64> %tmp11
-}
-
-//===---------------------------------------------------------------------===//
-
 These functions should produce the same code:
 
 #include <emmintrin.h>
@@ -671,43 +656,6 @@ beneficial because it prevents the load from being folded into the multiply.
 
 //===---------------------------------------------------------------------===//
 
-In this loop:
-
-bb49:		; preds = %bb49, %bb49.preheader
-	%indvar = phi i32 [ 0, %bb49.preheader ], [ %indvar.next, %bb49 ]		; <i32> [#uses=2]
-	%dp.089.0.rec = shl i32 %indvar, 3		; <i32> [#uses=2]
-	%dp.089.0 = getelementptr i32* %tmp89, i32 %dp.089.0.rec		; <i32*> [#uses=1]
-	%tmp5051 = bitcast i32* %dp.089.0 to <2 x i64>*		; <<2 x i64>*> [#uses=1]
-	store <2 x i64> zeroinitializer, <2 x i64>* %tmp5051, align 16
-	%dp.089.0.sum105 = or i32 %dp.089.0.rec, 4		; <i32> [#uses=1]
-	%tmp56 = getelementptr i32* %tmp89, i32 %dp.089.0.sum105		; <i32*> [#uses=1]
-	%tmp5657 = bitcast i32* %tmp56 to <2 x i64>*		; <<2 x i64>*> [#uses=1]
-	store <2 x i64> zeroinitializer, <2 x i64>* %tmp5657, align 16
-	%indvar.next = add i32 %indvar, 1		; <i32> [#uses=2]
-	%exitcond = icmp eq i32 %indvar.next, %tmp98		; <i1> [#uses=1]
-	br i1 %exitcond, label %bb72, label %bb49
-
-we get:
-
-LBB5_6:	# bb49.preheader
-	shlw	$2, %si
-	decw	%si
-	movzwl	%si, %eax
-	incl	%eax
-	xorl	%ecx, %ecx
-LBB5_7:	# bb49
-	xorps	%xmm0, %xmm0            # (1)
-	movaps	%xmm0, (%edx)
-	movaps	%xmm0, 16(%edx)
-	addl	$32, %edx
-	incl	%ecx
-	cmpl	%eax, %ecx
-	jne	LBB4_7	# bb47
-
-The instruction at (1) can be moved out of the main body of the loop.
-
-//===---------------------------------------------------------------------===//
-
 These functions:
 
 #include <xmmintrin.h>

test/CodeGen/X86/vec_set-8.ll

@@ -0,0 +1,10 @@
+; RUN: llvm-as < %s | llc -march=x86-64 | not grep movsd
+; RUN: llvm-as < %s | llc -march=x86-64 | grep {movd.*%rdi,.*%xmm0}
+
+define <2 x i64> @test(i64 %i) nounwind  {
+entry:
+	%tmp10 = insertelement <2 x i64> undef, i64 %i, i32 0
+	%tmp11 = insertelement <2 x i64> %tmp10, i64 0, i32 1
+	ret <2 x i64> %tmp11
+}
+