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      1 ; RUN: opt -instcombine -S < %s | FileCheck %s
      2 ; RUN: opt -passes=instcombine -S < %s | FileCheck %s
      3 
      4 ; This test makes sure that these instructions are properly eliminated.
      5 
      6 target datalayout = "e-m:e-p:64:64:64-i64:64-f80:128-n8:16:32:64-S128"
      7 
      8 @X = constant i32 42		; <i32*> [#uses=2]
      9 @X2 = constant i32 47		; <i32*> [#uses=1]
     10 @Y = constant [2 x { i32, float }] [ { i32, float } { i32 12, float 1.000000e+00 }, { i32, float } { i32 37, float 0x3FF3B2FEC0000000 } ]		; <[2 x { i32, float }]*> [#uses=2]
     11 @Z = constant [2 x { i32, float }] zeroinitializer		; <[2 x { i32, float }]*> [#uses=1]
     12 
     13 @GLOBAL = internal constant [4 x i32] zeroinitializer
     14 
     15 
     16 ; CHECK-LABEL: @test1(
     17 ; CHECK-NOT: load
     18 define i32 @test1() {
     19 	%B = load i32, i32* @X		; <i32> [#uses=1]
     20 	ret i32 %B
     21 }
     22 
     23 ; CHECK-LABEL: @test2(
     24 ; CHECK-NOT: load
     25 define float @test2() {
     26 	%A = getelementptr [2 x { i32, float }], [2 x { i32, float }]* @Y, i64 0, i64 1, i32 1		; <float*> [#uses=1]
     27 	%B = load float, float* %A		; <float> [#uses=1]
     28 	ret float %B
     29 }
     30 
     31 ; CHECK-LABEL: @test3(
     32 ; CHECK-NOT: load
     33 define i32 @test3() {
     34 	%A = getelementptr [2 x { i32, float }], [2 x { i32, float }]* @Y, i64 0, i64 0, i32 0		; <i32*> [#uses=1]
     35 	%B = load i32, i32* %A		; <i32> [#uses=1]
     36 	ret i32 %B
     37 }
     38 
     39 ; CHECK-LABEL: @test4(
     40 ; CHECK-NOT: load
     41 define i32 @test4() {
     42 	%A = getelementptr [2 x { i32, float }], [2 x { i32, float }]* @Z, i64 0, i64 1, i32 0		; <i32*> [#uses=1]
     43 	%B = load i32, i32* %A		; <i32> [#uses=1]
     44 	ret i32 %B
     45 }
     46 
     47 ; CHECK-LABEL: @test5(
     48 ; CHECK-NOT: load
     49 define i32 @test5(i1 %C) {
     50 	%Y = select i1 %C, i32* @X, i32* @X2		; <i32*> [#uses=1]
     51 	%Z = load i32, i32* %Y		; <i32> [#uses=1]
     52 	ret i32 %Z
     53 }
     54 
     55 ; CHECK-LABEL: @test7(
     56 ; CHECK-NOT: load
     57 define i32 @test7(i32 %X) {
     58 	%V = getelementptr i32, i32* null, i32 %X		; <i32*> [#uses=1]
     59 	%R = load i32, i32* %V		; <i32> [#uses=1]
     60 	ret i32 %R
     61 }
     62 
     63 ; CHECK-LABEL: @test8(
     64 ; CHECK-NOT: load
     65 define i32 @test8(i32* %P) {
     66 	store i32 1, i32* %P
     67 	%X = load i32, i32* %P		; <i32> [#uses=1]
     68 	ret i32 %X
     69 }
     70 
     71 ; CHECK-LABEL: @test9(
     72 ; CHECK-NOT: load
     73 define i32 @test9(i32* %P) {
     74 	%X = load i32, i32* %P		; <i32> [#uses=1]
     75 	%Y = load i32, i32* %P		; <i32> [#uses=1]
     76 	%Z = sub i32 %X, %Y		; <i32> [#uses=1]
     77 	ret i32 %Z
     78 }
     79 
     80 ; CHECK-LABEL: @test10(
     81 ; CHECK-NOT: load
     82 define i32 @test10(i1 %C.upgrd.1, i32* %P, i32* %Q) {
     83 	br i1 %C.upgrd.1, label %T, label %F
     84 T:		; preds = %0
     85 	store i32 1, i32* %Q
     86 	store i32 0, i32* %P
     87 	br label %C
     88 F:		; preds = %0
     89 	store i32 0, i32* %P
     90 	br label %C
     91 C:		; preds = %F, %T
     92 	%V = load i32, i32* %P		; <i32> [#uses=1]
     93 	ret i32 %V
     94 }
     95 
     96 ; CHECK-LABEL: @test11(
     97 ; CHECK-NOT: load
     98 define double @test11(double* %p) {
     99   %t0 = getelementptr double, double* %p, i32 1
    100   store double 2.0, double* %t0
    101   %t1 = getelementptr double, double* %p, i32 1
    102   %x = load double, double* %t1
    103   ret double %x
    104 }
    105 
    106 ; CHECK-LABEL: @test12(
    107 ; CHECK-NOT: load
    108 define i32 @test12(i32* %P) {
    109   %A = alloca i32
    110   store i32 123, i32* %A
    111   ; Cast the result of the load not the source
    112   %Q = bitcast i32* %A to i32*
    113   %V = load i32, i32* %Q
    114   ret i32 %V
    115 }
    116 
    117 ; CHECK-LABEL: @test13(
    118 ; CHECK-NOT: load
    119 define <16 x i8> @test13(<2 x i64> %x) {
    120   %tmp = load <16 x i8>, <16 x i8>* bitcast ([4 x i32]* @GLOBAL to <16 x i8>*)
    121   ret <16 x i8> %tmp
    122 }
    123 
    124 define i8 @test14(i8 %x, i32 %y) {
    125 ; This test must not have the store of %x forwarded to the load -- there is an
    126 ; intervening store if %y. However, the intervening store occurs with a different
    127 ; type and size and to a different pointer value. This is ensuring that none of
    128 ; those confuse the analysis into thinking that the second store does not alias
    129 ; the first.
    130 ; CHECK-LABEL: @test14(
    131 ; CHECK:         %[[R:.*]] = load i8, i8*
    132 ; CHECK-NEXT:    ret i8 %[[R]]
    133   %a = alloca i32
    134   %a.i8 = bitcast i32* %a to i8*
    135   store i8 %x, i8* %a.i8
    136   store i32 %y, i32* %a
    137   %r = load i8, i8* %a.i8
    138   ret i8 %r
    139 }
    140 
    141 @test15_global = external global i32
    142 
    143 define i8 @test15(i8 %x, i32 %y) {
    144 ; Same test as @test14 essentially, but using a global instead of an alloca.
    145 ; CHECK-LABEL: @test15(
    146 ; CHECK:         %[[R:.*]] = load i8, i8*
    147 ; CHECK-NEXT:    ret i8 %[[R]]
    148   %g.i8 = bitcast i32* @test15_global to i8*
    149   store i8 %x, i8* %g.i8
    150   store i32 %y, i32* @test15_global
    151   %r = load i8, i8* %g.i8
    152   ret i8 %r
    153 }
    154 
    155 define void @test16(i8* %x, i8* %a, i8* %b, i8* %c) {
    156 ; Check that we canonicalize loads which are only stored to use integer types
    157 ; when there is a valid integer type.
    158 ; CHECK-LABEL: @test16(
    159 ; CHECK: %[[L1:.*]] = load i32, i32*
    160 ; CHECK-NOT: load
    161 ; CHECK: store i32 %[[L1]], i32*
    162 ; CHECK: store i32 %[[L1]], i32*
    163 ; CHECK-NOT: store
    164 ; CHECK: %[[L1:.*]] = load i32, i32*
    165 ; CHECK-NOT: load
    166 ; CHECK: store i32 %[[L1]], i32*
    167 ; CHECK: store i32 %[[L1]], i32*
    168 ; CHECK-NOT: store
    169 ; CHECK: ret
    170 
    171 entry:
    172   %x.cast = bitcast i8* %x to float*
    173   %a.cast = bitcast i8* %a to float*
    174   %b.cast = bitcast i8* %b to float*
    175   %c.cast = bitcast i8* %c to i32*
    176 
    177   %x1 = load float, float* %x.cast
    178   store float %x1, float* %a.cast
    179   store float %x1, float* %b.cast
    180 
    181   %x2 = load float, float* %x.cast
    182   store float %x2, float* %b.cast
    183   %x2.cast = bitcast float %x2 to i32
    184   store i32 %x2.cast, i32* %c.cast
    185 
    186   ret void
    187 }
    188 
    189 define void @test17(i8** %x, i8 %y) {
    190 ; Check that in cases similar to @test16 we don't try to rewrite a load when
    191 ; its only use is a store but it is used as the pointer to that store rather
    192 ; than the value.
    193 ;
    194 ; CHECK-LABEL: @test17(
    195 ; CHECK: %[[L:.*]] = load i8*, i8**
    196 ; CHECK: store i8 %y, i8* %[[L]]
    197 
    198 entry:
    199   %x.load = load i8*, i8** %x
    200   store i8 %y, i8* %x.load
    201 
    202   ret void
    203 }
    204