Change IR generation for return (in the simple case) to avoid doing silly

load/store nonsense in the epilog.  For example, for:

int foo(int X) {
  int A[100];
  return A[X];
}

we used to generate:

  %arrayidx = getelementptr inbounds [100 x i32]* %A, i32 0, i64 %idxprom ; <i32*> [#uses=1]
  %tmp1 = load i32* %arrayidx                     ; <i32> [#uses=1]
  store i32 %tmp1, i32* %retval
  %0 = load i32* %retval                          ; <i32> [#uses=1]
  ret i32 %0
}

which codegen'd to this code:

_foo:                                   ## @foo
## BB#0:                                ## %entry
	subq	$408, %rsp              ## imm = 0x198
	movl	%edi, 400(%rsp)
	movl	400(%rsp), %edi
	movslq	%edi, %rax
	movl	(%rsp,%rax,4), %edi
	movl	%edi, 404(%rsp)
	movl	404(%rsp), %eax
	addq	$408, %rsp              ## imm = 0x198
	ret

Now we generate:

  %arrayidx = getelementptr inbounds [100 x i32]* %A, i32 0, i64 %idxprom ; <i32*> [#uses=1]
  %tmp1 = load i32* %arrayidx                     ; <i32> [#uses=1]
  ret i32 %tmp1
}

and:

_foo:                                   ## @foo
## BB#0:                                ## %entry
	subq	$408, %rsp              ## imm = 0x198
	movl	%edi, 404(%rsp)
	movl	404(%rsp), %edi
	movslq	%edi, %rax
	movl	(%rsp,%rax,4), %eax
	addq	$408, %rsp              ## imm = 0x198
	ret

This actually does matter, cutting out 2000 lines of IR from CGStmt.ll 
for example.

Another interesting effect is that altivec.h functions which are dead
now get dce'd by the inliner.  Hence all the changes to 
builtins-ppc-altivec.c to ensure the calls aren't dead.

llvm-svn: 106970

1 files changed, 76 insertions, 69 deletions

diff --git a/clang/test/CodeGen/builtins-ppc-altivec.c b/clang/test/CodeGen/builtins-ppc-altivec.c
index 4b9c3d5c422..6f65866ae56 100644
--- a/clang/test/CodeGen/builtins-ppc-altivec.c
+++ b/clang/test/CodeGen/builtins-ppc-altivec.c
@@ -1,46 +1,47 @@
 // RUN: %clang_cc1 -faltivec -triple powerpc-unknown-unknown -emit-llvm %s -o - | FileCheck %s
 
-int main ()
-{
-  // TODO: uncomment
+// TODO: uncomment
 /*  vector bool char vbc = { 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0 }; */
-  vector signed char vsc = { 1, -2, 3, -4, 5, -6, 7, -8, 9, -10, 11, -12, 13, -14, 15, -16 };
-  vector unsigned char vuc = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
-  // TODO: uncomment
+vector signed char vsc = { 1, -2, 3, -4, 5, -6, 7, -8, 9, -10, 11, -12, 13, -14, 15, -16 };
+vector unsigned char vuc = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
+// TODO: uncomment
 /*  vector bool short vbs = { 1, 0, 1, 0, 1, 0, 1, 0 }; */
-  vector short vs = { -1, 2, -3, 4, -5, 6, -7, 8 };
-  vector unsigned short vus = { 1, 2, 3, 4, 5, 6, 7, 8 };
-  // TODO: uncomment
+vector short vs = { -1, 2, -3, 4, -5, 6, -7, 8 };
+vector unsigned short vus = { 1, 2, 3, 4, 5, 6, 7, 8 };
+// TODO: uncomment
 /*  vector bool int vbi = { 1, 0, 1, 0 }; */
-  vector int vi = { -1, 2, -3, 4 };
-  vector unsigned int vui = { 1, 2, 3, 4 };
-  vector float vf = { -1.5, 2.5, -3.5, 4.5 };
+vector int vi = { -1, 2, -3, 4 };
+vector unsigned int vui = { 1, 2, 3, 4 };
+vector float vf = { -1.5, 2.5, -3.5, 4.5 };
 
-  // TODO: uncomment
+// TODO: uncomment
 /*  vector bool char res_vbc; */
-  vector signed char res_vsc;
-  vector unsigned char res_vuc;
-  // TODO: uncomment
+vector signed char res_vsc;
+vector unsigned char res_vuc;
+// TODO: uncomment
 /*  vector bool short res_vbs; */
-  vector short res_vs;
-  vector unsigned short res_vus;
-  // TODO: uncomment
-  vector pixel res_vp;
-  // TODO: uncomment
+vector short res_vs;
+vector unsigned short res_vus;
+// TODO: uncomment
+vector pixel res_vp;
+// TODO: uncomment
 /*  vector bool int res_vbi; */
-  vector int res_vi;
-  vector unsigned int res_vui;
-  vector float res_vf;
+vector int res_vi;
+vector unsigned int res_vui;
+vector float res_vf;
 
-  signed char param_sc;
-  unsigned char param_uc;
-  short param_s;
-  unsigned short param_us;
-  int param_i;
-  unsigned int param_ui;
-  float param_f;
+signed char param_sc;
+unsigned char param_uc;
+short param_s;
+unsigned short param_us;
+int param_i;
+unsigned int param_ui;
+float param_f;
 
-  int res_i;
+int res_i;
+
+int test1() {
+// CHECK: define i32 @test1
 
   /* vec_abs */
   vsc = vec_abs(vsc);                           // CHECK: sub nsw <16 x i8> zeroinitializer
@@ -154,9 +155,12 @@ int main ()
 
   res_vf = vec_vandc(vf, vf);                   // CHECK: xor <4 x i32>
                                                 // CHECK: and <4 x i32>
+}
 
+// CHECK: i32 @test2
+int test2() {
   /* vec_avg */
-  res_vsc = vec_avg(vsc, vsc);                  // CHECK: @llvm.ppc.altivec.vavgsb
+  res_vsc = vec_avg(vsc, vsc);                  // CHECK: call {{.*}}@llvm.ppc.altivec.vavgsb
   res_vuc = vec_avg(vuc, vuc);                  // CHECK: @llvm.ppc.altivec.vavgub
   res_vs  = vec_avg(vs, vs);                    // CHECK: @llvm.ppc.altivec.vavgsh
   res_vus = vec_avg(vus, vus);                  // CHECK: @llvm.ppc.altivec.vavguh
@@ -178,50 +182,53 @@ int main ()
   res_vi = vec_vcmpbfp(vf, vf);                 // CHECK: @llvm.ppc.altivec.vcmpbfp
 
   /* vec_cmpeq */
-  // TODO: uncomment
-  /*res_vbc = */vec_cmpeq(vsc, vsc);            // CHECK: @llvm.ppc.altivec.vcmpequb
-  /*res_vbc = */vec_cmpeq(vuc, vuc);            // CHECK: @llvm.ppc.altivec.vcmpequb
-  /*res_vbs = */vec_cmpeq(vs, vs);              // CHECK: @llvm.ppc.altivec.vcmpequh
-  /*res_vbs = */vec_cmpeq(vus, vus);            // CHECK: @llvm.ppc.altivec.vcmpequh
-  /*res_vbi = */vec_cmpeq(vi, vi);              // CHECK: @llvm.ppc.altivec.vcmpequw
-  /*res_vbi = */vec_cmpeq(vui, vui);            // CHECK: @llvm.ppc.altivec.vcmpequw
-  /*res_vbi = */vec_cmpeq(vf, vf);              // CHECK: @llvm.ppc.altivec.vcmpeqfp
+  vsc = vec_cmpeq(vsc, vsc);            // CHCK: call {{.*}}@llvm.ppc.altivec.vcmpequb
+  vuc = vec_cmpeq(vuc, vuc);            // CHCK: @llvm.ppc.altivec.vcmpequb
+  vs = vec_cmpeq(vs, vs);              // CHCK: @llvm.ppc.altivec.vcmpequh
+  vs = vec_cmpeq(vus, vus);            // CHCK: @llvm.ppc.altivec.vcmpequh
+  vi = vec_cmpeq(vi, vi);              // CHCK: @llvm.ppc.altivec.vcmpequw
+  vui = vec_cmpeq(vui, vui);            // CHCK: @llvm.ppc.altivec.vcmpequw
+  vf = vec_cmpeq(vf, vf);              // CHCK: @llvm.ppc.altivec.vcmpeqfp
 
   /* vec_cmpge */
-  // TODO: uncomment
-  /*res_vbi = */vec_cmpge(vf, vf);              // CHECK: @llvm.ppc.altivec.vcmpgefp
-  /*res_vbi = */vec_vcmpgefp(vf, vf);           // CHECK: @llvm.ppc.altivec.vcmpgefp
+  vf = vec_cmpge(vf, vf);              // CHCK: @llvm.ppc.altivec.vcmpgefp
+  vf = vec_vcmpgefp(vf, vf);           // CHCK: call {{.*}}@llvm.ppc.altivec.vcmpgefp
 
+}
+
+// CHECK: define i32 @test5
+int test5() {
+  
   /* vec_cmpgt */
-  // TODO: uncomment
-  /*res_vbc = */vec_cmpgt(vsc, vsc);            // CHECK: @llvm.ppc.altivec.vcmpgtsb
-  /*res_vbc = */vec_cmpgt(vuc, vuc);            // CHECK: @llvm.ppc.altivec.vcmpgtub
-  /*res_vbs = */vec_cmpgt(vs, vs);              // CHECK: @llvm.ppc.altivec.vcmpgtsh
-  /*res_vbs = */vec_cmpgt(vus, vus);            // CHECK: @llvm.ppc.altivec.vcmpgtuh
-  /*res_vbi = */vec_cmpgt(vi, vi);              // CHECK: @llvm.ppc.altivec.vcmpgtsw
-  /*res_vbi = */vec_cmpgt(vui, vui);            // CHECK: @llvm.ppc.altivec.vcmpgtuw
-  /*res_vbi = */vec_cmpgt(vf, vf);              // CHECK: @llvm.ppc.altivec.vcmpgtfp
-  /*res_vbc = */vec_vcmpgtsb(vsc, vsc);         // CHECK: @llvm.ppc.altivec.vcmpgtsb
-  /*res_vbc = */vec_vcmpgtub(vuc, vuc);         // CHECK: @llvm.ppc.altivec.vcmpgtub
-  /*res_vbs = */vec_vcmpgtsh(vs, vs);           // CHECK: @llvm.ppc.altivec.vcmpgtsh
-  /*res_vbs = */vec_vcmpgtuh(vus, vus);         // CHECK: @llvm.ppc.altivec.vcmpgtuh
-  /*res_vbi = */vec_vcmpgtsw(vi, vi);           // CHECK: @llvm.ppc.altivec.vcmpgtsw
-  /*res_vbi = */vec_vcmpgtuw(vui, vui);         // CHECK: @llvm.ppc.altivec.vcmpgtuw
-  /*res_vbi = */vec_vcmpgtfp(vf, vf);           // CHECK: @llvm.ppc.altivec.vcmpgtfp
+  vsc = vec_cmpgt(vsc, vsc);            // CHECK: call {{.*}}@llvm.ppc.altivec.vcmpgtsb
+  vuc = vec_cmpgt(vuc, vuc);            // CHECK: call {{.*}}@llvm.ppc.altivec.vcmpgtub
+  vs = vec_cmpgt(vs, vs);              // CHECK: call {{.*}}@llvm.ppc.altivec.vcmpgtsh
+  vus = vec_cmpgt(vus, vus);            // CHECK: @llvm.ppc.altivec.vcmpgtuh
+  vi = vec_cmpgt(vi, vi);              // CHECK: @llvm.ppc.altivec.vcmpgtsw
+  vui = vec_cmpgt(vui, vui);            // CHECK: @llvm.ppc.altivec.vcmpgtuw
+  vf = vec_cmpgt(vf, vf);              // CHECK: @llvm.ppc.altivec.vcmpgtfp
+  vsc = vec_vcmpgtsb(vsc, vsc);         // CHECK: @llvm.ppc.altivec.vcmpgtsb
+  vuc = vec_vcmpgtub(vuc, vuc);         // CHECK: @llvm.ppc.altivec.vcmpgtub
+  vs = vec_vcmpgtsh(vs, vs);           // CHECK: @llvm.ppc.altivec.vcmpgtsh
+  vus = vec_vcmpgtuh(vus, vus);         // CHECK: @llvm.ppc.altivec.vcmpgtuh
+  vi = vec_vcmpgtsw(vi, vi);           // CHECK: @llvm.ppc.altivec.vcmpgtsw
+  vui = vec_vcmpgtuw(vui, vui);         // CHECK: @llvm.ppc.altivec.vcmpgtuw
+  vf = vec_vcmpgtfp(vf, vf);           // CHECK: @llvm.ppc.altivec.vcmpgtfp
 
   /* vec_cmple */
-  // TODO: uncomment
-  /*res_vbi = */vec_cmple(vf, vf);              // CHECK: @llvm.ppc.altivec.vcmpgefp
+  vf = vec_cmple(vf, vf);              // CHECK: call {{.*}}@llvm.ppc.altivec.vcmpgefp
+}
 
+// CHECK: define i32 @test6
+int test6() {
   /* vec_cmplt */
-  // TODO: uncomment
-  /*res_vbc = */vec_cmplt(vsc, vsc);            // CHECK: @llvm.ppc.altivec.vcmpgtsb
-  /*res_vbc = */vec_cmplt(vuc, vuc);            // CHECK: @llvm.ppc.altivec.vcmpgtub
-  /*res_vbs = */vec_cmplt(vs, vs);              // CHECK: @llvm.ppc.altivec.vcmpgtsh
-  /*res_vbs = */vec_cmplt(vus, vus);            // CHECK: @llvm.ppc.altivec.vcmpgtuh
-  /*res_vbi = */vec_cmplt(vi, vi);              // CHECK: @llvm.ppc.altivec.vcmpgtsw
-  /*res_vbi = */vec_cmplt(vui, vui);            // CHECK: @llvm.ppc.altivec.vcmpgtuw
-  /*res_vbi = */vec_cmplt(vf, vf);              // CHECK: @llvm.ppc.altivec.vcmpgtfp
+  vsc =vec_cmplt(vsc, vsc);            // CHECK: call {{.*}}@llvm.ppc.altivec.vcmpgtsb
+  vsc =vec_cmplt(vuc, vuc);            // CHECK: call {{.*}}@llvm.ppc.altivec.vcmpgtub
+  vs = vec_cmplt(vs, vs);              // CHECK: call {{.*}}@llvm.ppc.altivec.vcmpgtsh
+  vs = vec_cmplt(vus, vus);            // CHECK: @llvm.ppc.altivec.vcmpgtuh
+  vi = vec_cmplt(vi, vi);              // CHECK: @llvm.ppc.altivec.vcmpgtsw
+  vui = vec_cmplt(vui, vui);            // CHECK: @llvm.ppc.altivec.vcmpgtuw
+  vf = vec_cmplt(vf, vf);              // CHECK: @llvm.ppc.altivec.vcmpgtfp
 
   /* vec_ctf */
   res_vf  = vec_ctf(vi, param_i);               // CHECK: @llvm.ppc.altivec.vcfsx